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MAY,  1915  MEMOIR  No.  6 

CORNELL  UNIVERSITY 
AGRICULTURAL    EXPERIMENT   STATION 

OF  THE  COLLEGE  OF  AGRICULTURE 


FUSARIA  OF  POTATOES 


BY  C.  D. SHERBAKOFF 

FORMERLY  OF  THE  DEPARTMENT  OF  PLANT  PATHOLOGY,  CORNELL  UNIVERSITY 
NOW  ASSOCIATE  PLANT  PATHOLOGIST,  AGRICULTURAL  EXPERIMENT  STATION,  UNIVERSITY  OF  FLORIDA 


ITHACA,  NEW  YORK 
PUBLISHED  BY  THE  UNIVERSITY 


■'♦^#. Jl  HltLLIBRARY 
i-  Ci^TAtE-tiNIVERSITY 


CORNELL  UNIVERSITY 
AGRICULTURAL  EXPERIMENT  STATION 

Experimenting  Staff 

BEVERLY  T.  GALLOWAY,  B.Agr.Sc,  LL.D.,  Director. 

ALBERT  R.  MANN,  B.S.A.,  Secretary. 

JOHN  H.  COMSTOCK,  B.S.,  Entomology. 

HENRY  H.  WING.  M.S.  in  Agr.,  Animal  Husbandry. 

T.  LYTTLETON  LYON,  Ph.D.,  SoU  Technology. 

JOHN  L.  STONE,  B.Agr.,  Farm  Practice. 

JAMES  E.  RICE,  B.S.A.,  Poultry  Husbandry 

GEORGE  W.  CAVANAUGH,  B.S.,  Agricultural  Chemistry. 

HERBERT  H.  WHETZEL,  M.A.,  Plant  Pathology. 

ELMER  O.  PIPPIN,   B.S.A.,  Soil  Technology. 

G.  F.  WARREN,  Ph.D.,  Farm  Management. 

WILLIAM  A.   STOCKING,  Jr..  M.S.A,,  Dairy  Industry. 

WILFORD  M.  WILSON.   M.D.,  Meteorology. 

RALPH  S.  HOSMER,  M.F.,  Forestry. 

JAMES  G.    NEEDHAM,  Ph.D.,  Entomology  and  Limnology. 

ROLLINS  A.   EMERSON,    Ph.D.,  Plant  Breeding. 

HARRY  H.   L0\^,    Ph.D.,  Plant  Breeding. 

ARTHUR   W.  GILBERT,  Ph.D..  Plant  Breeding. 

DONALD    REDDICK,  Ph.D.,  Plant  Pathology. 

EDWARD   G.   MONTGOMERY,   M.A.,  Farm  Crops. 

WILLIAM  A.    RILEY,  Ph.D.,  Entomology. 

MERRITT  W.    HARPER.   M.S.,  Animal  Husbandry. 

J.  A.   BIZZELL.    Ph.D.,  Soil  Technology. 

GLENN   W.  HERRICK,   B.S  A.,  Economic  Entomology. 

HOWARD   W.  RILEY.   M.E..  Farm  Mechanics. 

CYRUS  R.   CROSBY.   A.B..  Entomology. 

HAROLD  E.   ROSS.   M.S.A. ,  Dairy  Industry. 

KARL  McK.    WIEGAND,  Ph.D..  Botany. 

EDWARD  A.   WHITE.   PS..  Floriculture. 

WILLIAM  H.    CHANDLER.   ISLS.  in  Agr.,  Pomology. 

ELMER    S.   SAVAGE.   IVLS.A.,  Ph.D.,  Animal  Husbandry. 

LEWIS    KNUDSON.  PhD..  Plant  Physiology. 

KENNETH    C.   LIVERMORE,  B.S.  in  Agr..  Farm  Management. 

ALVIN  C.    PEAL,  Ph.D.,  Floriculture. 

MORTIER    F.  BARRUS,  Ph.D7,  Plant  Pathology. 

CLYDE   H.    MYERS,  M.S.,  Ph.D.,  Plant  Breeding. 

GEORGE    W.  TAILBY,  Jr.,  B.S. A.,  Superintendent  of  Live-stock. 

EDWARD    S.  GUTHRIE,   ^^S.  in  .\gr.,  Ph.D.,  Dairy  Industry. 

JAMES  C.    BRADLEY,  Ph.D.,  Entomology. 

PAUL   WORK,   B.S.,  A.B.,  Vegetable  Gardemng. 

JOHN    BENTLEY,  Jr.,  B.S..   ^LF..  Forestry. 

EARL  W.   BENJAMIN.   Ph.D.,  Poultry  Husbandry. 

EMMONS   W.   LELAND.   B.S. A.,  Soil  Technology. 

CHARLES  T.   GREGORY.   Ph.D.,  Plant  Pathology. 

WALTER  W.  FISK,   M.S.A.,   Dairy  Indu.stry. 

ARTHUR  L.  THOMPSON,  M.S.  in  Agr.,  Farm  Management. 

ROBERT   MATHESON.   Ph.D..  Entomology. 

HORACE   M.   PICKERILL.  B.S.,  Dairy  Industry. 

MORTIMER  D.   LEONARD,   B.S..  Entomology. 

FRANK  E.  RICE.   Ph.D..  Agricultural  Chemistry. 

V.  B.  STEWART,  Ph.D..  Plant  Pathology.  .  ,    t^     ,  tt   •  *    s 

IVAN  C    JAGGER.  M.S..  Plant  Pathology  (In  cooperation  with  Rochester  Umversity). 

CHARLES  H.  HADLEY,  B.S..  Entomology. 

BRISTOW  ADAMS,  B  A.,  Editor. 

LELA  G.  GROSS,  Assistant  Editor. 

The  regular  bulletins  of  the  Station  are  sent  free  on  request  to  residents  of  New  York  State. 


87 


CONTENTS 

PAGE 

Introductory 97 

Scope  of  work 100 

Source  and  methods  of  isolation 101 

Culture  media 104 

Effect  of  various  media  on  different  characters  of  Fusaria 106 

Effect  of  light  and  of  reaction  of  the  medium  on  different  characters 

of  Fusaria 107 

The  genus  Fusarium 108 

Variability  in  the  Fusaria Ill 

Relative  taxonomic  importance  of  different  characters 113 

Forms  of  fructification  in  pure  cultures 114 

Spores 114 

Forms  of  fructification 114 

Method  of  study  and  presentation 116 

Identification  of  the  Fusaria  with  previously  described  species 120 

Systematic  arrangement  of  the  species  of  Fusarium  of  potatoes 121 

Dichotomous   key    to  the   species   of  Fusarium   and   Fusarium-like 

fungi  of  potatoes 123 

Descriptions  of  sections,  genera,  species,  and  varieties 125 

Literature  cited 269 


INDEX  OF  SECTIONS,  GENERA,  SPECIES,  AND  VARIETIES 

(Pages  of  main  references  are  in  bold-faced  type) 

PAGE 
ARTHROSPORIELLA 124,    l6l,    183 

Atractium 108,  109 

Cylindrocarpon 109 

DiMERUM 123,  125 

DISCOLOR 124,  142,  228,  229,  231 

ELEGANS 115,  124,  128,  183,  202,  206,  215,  228,  262 

EUPIONNOTES 123,    I3I 

FERRUGINOSUM 124,  186,  190,  228 

Fusarium 97,  98,  99,  101,  108,  109,  110,  111,  114,  117,  121 

122,  123,  125,  143,  229,  262,  264 

acuminatum 123,  142 

affine 98,  113,  122,  123,  126,  127 

anguioides 122,  124,  169,  170,  173,  183,  187,  188 

anguioides  var.  caudatum 173 

angustum. 106,  117,  122,  124,  203 

aquaeductum 109 

arcuosporum 102,  106,  122,  124,  169,  186,  187,  190 

argillaceum 121 

arthrosporioides 122,  124,  161,  175,  176,  179 

arthrosporioides  var.  asporotrichius 103,  122,   179 

biforme 122,  124,  154,  166,  170,  176 

bullatum 122,  124,  198,  199,  201 

bullatum  var.  roseum 103,  184,  198,  201,  202 

caudatum 99,  141 

caudatum  var.  Solani 122,  123,  140 

citrinum 121 

clavatum 122,  125,  234,  235,  237 

coeruleum 98,  100,  122,  125,  173,  180,  231,  234,  260,  261,  262 

conglutinans 121,  183,  206 

corallinum 241 

91 


92  Index  of  Sections,  Genera,  Species,  and  Varieties 

Fusarium  (continued)  page 

culmorum 99,  125,  240,  241,  242 

culmorum  var.  leteius 122,  239,  242,  243 

cuneiforme 110,  112,  113,  115,  122,  123,  128,  129 

diffusum 166 

dimerum 98,  113,  122,  123,  127,  128 

dimerum  var.  Solani 102 

diplosporum 182 

discolor 98,  99,  122,  125,  229,  236,  237,  238,  239,  240 

discolor  var.  sulphureum 115,  238 

discolor  var.  triseptatum 122,  239 

'       diversisporum 103,  112,  124,  143,  154,  161,  162,  166 

dydimum 108,  109,  264 

effusum 123,  151,  152,  154,  158 

falcatum 99,  115,  122,  123,  135,  136  139 

falcatum  var.  fuscum 123,  138 

ferruginosum 122,  124,  190,  191 

gibbosum 122,  123,  133,  134,  136 

Helianthi 183 

lucidum 122,  123,  154,  157,  158 

lutulatum 122,  124,  209,  214,  262 

lutulatum  var.  zonatum 194,  214 

Martii 98,  99,  122,  125,  231,  244,  245,  247,  249,  251,  255,  258 

Martii  var.  minus 245,  249,  258 

Martii  var.  viride 245,  247,  249,  258 

metacroum 98,  99,  103,  115,  123,  143,  144,  145,  162 

metacroum  var.  minus 101,  103,  145,  146 

orthoceras 109,  122,  124,  183,  202,  203 

oxysporum 97,  98,  99,  111,  122,  124,  184,  196,  203,  204,  205 

206,  220,  221,  222,  224,  226 

oxysporum  var.  asclerotium 221,  222 

oxysporum  var.  longius.' 122,  223,  224,  227 

oxysporum  var.  resupinatum 122,  198,  214,  226 

pirinum 121 ,  183 

Poffi 183 

radicicola 98,  125,  257,  258 

redolens 99,  205,  206 


Index  of  Sections,  Genera,  Species,  and  Varieties  93 

Fusarium  {concluded)  page 

redolens  var.  Solani 122,  124,  205,  206 

rubiginosum 241 

sanguineum 124,  193,  194,  196,  214 

sanguineum  var.  pallidium 122,  196,  197 

Schribauxi 241 

sclerotioides 108,  122,  124,  214,  215,  218 

sclerotioides  var.  brcvius 218 

sclerotium 116 

Solani 98,  99,  122,  125,  152,  180,  183.  184,  251,  253,  254,  255 

Solani  var.  cyanum 231,  251,  253,  254 

Solani  var.  suffuscum 251,  254 

sporotrichioides 113,  114,  122,  124,  183,  183,  184 

striatum 122,  125,  255,  258,  259,  262 

subpallidum 124,  230,  231.  233 

subpallidum  var.  roseum 122,  233 

subulatum 98,  99,  115,  122,  123,  147,  148,  149,  150,  154,  262 

subulatum  var.  brevius 148,  149,  262 

trichothecioides 98,  111,  114,  122,  124,  229,  230,  262 

truncatum 122,  123,  155,  157 

tuberivorum Ill,  229,  230 

udum 99,  109,  123,  131,  132 

udum  var.  Solani 102,  109,  112,  113,  115,  122,  131,  132,  269 

vasinfectum  var.  Pisi 135 

ventricosum 123,  128,  129 

violaceum 260 

Willkommi 108,  109 

Fusidium 108 

udum 131 

Fusisporium 108 

Fusoma % 108 

gibbosum 116,  123,  133 

martiella 115,  125.  228,  244,  261 

Pionnotes 108,  109 

uda 131 

Ramularia 99,  109,  123,  264,  269 

Candida 265,  266 


94  Index  of  Sections,  Genera,  Species,  and  Varieties 

Ramularia  (concluded)  page 

didyma 264 

eudidyma 122,  123,  264,  265 

macrospora 269 

Magnusiana 102,  122,  123,  265,  266 

Solani 122,  123,  132,  267,  269 

ROSEUM 116,  123,  142,  161,  186,  190,  228 

Selenosporium 108 

Sepedonium 109 

SPOROTRICHIELLA 124,    161,    183 

VENTRICOSUM 123,    I28 


FUSARIA  OF  POTATOES 


FUSARIA  OF  POTATOES  1 

C.  D.  Sherbakoff 

INTRODUCTORY 

The  purpose  of  this  work  has  been  to  lay  down  a  basis  for  the  study 
of  the  disease  known  as  the  fusarial  wilt  and  dry  rot  of  potatoes,  Solarium 
tuberosum. 

On  the  basis  of  previous  work  done  by  various  mycologists  and  plant 
pathologists  on  Fusaria  of  potatoes,  it  was  evident,  even  before  the 
monographic  work  of  Appel  and  Wollenweber  (1910),  that  the  potato 
is  a  host  of  a  number  of  different  species  of  Fusarium.  At  the  same  time 
the  descriptions  of  these  organisms  were,  almost  without  exception,  so 
confusing,  and  the  organisms  as  a  rule  were  apparently  so  variable,  that 
there  was  no  sure  way  of  identifying  a  Fusarium  isolated  from  potato 
with  a  previously  described  Fusarium  even  of  the  same  host.  Such  a 
state  of  affairs  led  Smith  and  Swingle  (1904:50)  to  make  a  general  state- 
ment as  follows:  "Many  specific  names  have  been  given  to  Fusaria 
growing  on  the  potato,  and  while  some  of  these  names  may  stand  for 
distinct  forms,  this  is  not  at  all  certain.  Most  of  these  names  undoubtedly 
are  synonyms,  and  for  the  purpose  of  this  paper  all  are  regarded  as  such." 

On  the  other  hand,  Lindau  (1908)  and  others  continued  to  believe 
firmly  that  there  were  different  Fusaria  of  potatoes,  and  that  Fusarium 
oxysporum  as  described  by  Smith  and  Swingle  is  nothing  else  than  a 
"  Mischart." 

Whether  more  than  one  species  of  Fusarium  occurs  on  this  host  and, 
if  more  than  one,  on  what  basis  they  could  be  separated,  was  then  the 
question  which  in  the  opinion  of  the  writer  needed  to  be  definitely  settled 
before  any  pathological  work  with  these  organisms  could  be  properly 
done.  This  involved  the  accumulation  of  as  many  different  strains  of 
the  Fusaria  as  was  practicable,  from  all  available  sources,  and  their  com- 
parison in  pure  culture  on  various  suitable  media  and  under  the  same 
conditions  of  growth.  On  this  basis  the  work  has  been  carried  on  since 
the  autumn  of  1911. 

'  Presented  to  the  Faculty  of  the  Graduate  School  of  Cornell  University  as  a  major  thesis  in  partial 
fulfillment  of  the  requirements  for  the  degree  of  doctor  of  philosophy. 

97 


98  ■  C.  D.  Sherbakoff 

When  the  work  was  well  under  way  and  it  became  apparent  that  there 
are  indeed  a  considerable  number  of  species  of  Fusarium,  it  came  to 
the  writer's  knowledge  that  the  same  thing  was  definitely  proved,  at 
least  for  European  conditions,  by  Appel  and  Wollenweber  (1910)  in 
their  Grundlagen  (page  105),  in  which  they  state  that  most  of  the  Fusaria 
described  by  them  were  isolated  from  the  potato,  mainly  from  the  tubers. 
Since  then  this  work  has  been  continued  with  still  greater  confidence 
in  its  underlying  principles,  but  now  mainly  in  order  to  verify  the  European 
findings  for  the  American  conditions.^ 

All  cultures  of  the  Fusaria  were  obtained  by  isolations  made  from 
diseased  parts  of  the  potato  plant,  mainly  from  tubers  received  from 
pathologists  in  nearly  every  experiment  station  in  the  United  States. 
Of  all  the  strains  of  the  Fusarium-like  organisms  thus  obtained,  over 
one  hundred  and  twenty  organisms  at  first  seemed  to  differ  in  some  way 
or  another.  After  a  careful  comparative  study  of  all  these  strains,  more 
than  half  of  the  number  proved  to  be  identical  with  others. 

Some  of  the  remaining  organisms  were  identified  with  several  Fusaria 
described  by  Appel  and  Wollenweber  (1910),  by  Jamieson  and  Wollen- 
weber (1912),  and  by  Wollenweber  (1913,  b  and  c).     These  are  as  follows: 

Fusarium  ajffine  Faut.  et  Lamb. 

F.  coeruleum  (Lib.)  Sacc. 

F.  dimerum  Penz, 

F.  discolor  Ap.  et  Wr. 

F.  Martii  Ap.  et  Wr. 

F.  metacroum  Ap.  et  Wr. 

F.  oxysporuni  Schlecht.,  as  described  by  Wollenweber 

F.  radicicola  Wr.  *■ 

F.  Solani  (Mart.  p.  par.)  Ap.  et  Wr. 

F.  suhidatum  Ap.  et  Wr. 

F.  trichothecioides  Wr. 

Still  other  organisms  were  found  to  be  very  closely  related  either  to 
some  of  the  species  named  above  or  to  certain  other  species,  at  the 
same  time  differing  sufficiently  from  them  to  be  separated  on  a  con- 

2  The  general  discussion  of  the  genus  Fusarium  was  known  to  the  writer  before  he  began  his  work,  when 
in  the  summer  of  1911  Dr.  Jensen  received  the  Grundlagen  and  now  and  then  read  parts  of  it  to  the  writer. 
Having  no  idea  that  Appel  and  Wollenweber  were  working  mainly  with  the  Fusaria  of  the  potato,  the  writer 
did  not  study  their  work  thoroughly  as  early  as  he  should  have. 


FusARiA  OF  Potatoes  99 

servative  basis  from  those  species.     These  organisms  were  then  designated 
as  new  varieties  of  the  following  old  species: 

Fusarium  caudatum  Wr.  (one  new  variety) 

F.  culmorum  (W.  Smith)  Sacc.  (one  new  variety) 

F.  discolor  Ap.  et  Wr.  (one  new  variety) 

F.  falcatum  Ap.  et  Wr.  (one  new  variety) 

F.  Martii  Ap.  et  Wr.  (two  new  varieties) 

F.  metacroum  Ap.  et  Wr.  (one  new  variety) 

F.  oxysporum  Schlecht.  (three  new  varieties) 

F.  redolens  Wr.  (one  new  variety) 

F.  Solani  (Mart.  p.  par.)  Ap.  et  Wr.  (two  new  varieties) 

F.  suhulatum  Ap.  et  Wr.  (one  new  variety) 

F.  udum  (Berk.)  Wr.  (one  new  variety) 

The  remaining  organisms  of  the  genus  Fusarium  were  then  named  as 
new  species  and  their  varieties.  It  is  probable  that  at  least  some  of  them 
have  been  previously  described,  but  the  descriptions  given  are  so  incom- 
plete that  any  reasonable  identification  is  doubtful.  The  matter  of  identi- 
fication is  discussed  on  another  page. 

Besides  the  Fusaria,  several  organisms  were  isolated  in  the  course  of 
the  work  which  more  or  less  closely  resemble  Fusarium  though  belonging 
to  a  different  genus  (Ramularia)  of  the  Hyphomycetes.  As  these  organ- 
isms are  often  found  on  the  potato  and  are  easily  confused  with  species 
of  Fusarium,  they  are  treated  here,  but  of  course  under  their  proper  generic 
name. 

On  the  whole  the  work,  with  a  few  exceptions,  fully  verifies  the  princi- 
ples laid  down  by  Appel  and  Wollenweber  (1910).  The  chief  exceptions 
are  as  follows:  (1)  The  Fusaria  as  such  can  be  distinguished  on  almost 
any  medium,  including  artificial  media,  provided  that  the  medium  is  not 
extremely  poor  or  rich  in  food  materials  and  also  provided  that  the  moisture 
supply  in  the  medium  is  well  regulated.  (2)  The  microconidia  should 
be  recognized  as  a  special  kind  of  spores  because  of  their  importance  in 
classification  of  these  fungi.  Though  microconidia  genetically  do  not 
represent  a  separate  kind  of  spores,  nevertheless  their  typical  absence 
for  certain  closely  related  Fusaria,  as  well  as  their  typical  presence  for 
others,  is  characteristic.  Besides,  whenever  they  are  present  they  have 
a  constant  and  often  distinctive  type  of  their  own.     (3)  No  typical  core- 


100  C.  D.  Sherbakoff 

mial  nor  typical  pionnotal  form  of  fructification  was  observed  in  any  of 
the  true  Fusaria,  though  types  of  fructification  resembling  those  forms 
more  or  less  closely  were  common. 

SCOPE  OF  WORK 

The  work  was  confined  to  a  study  of  the  Fusaria  as  such,  that  is,  without 
any  consideration  of  the  possible  perfect  forms.^  The  study  was  centered 
mainly  on  the  characters  that  seem  to  be  most  important  and  practicable 
for  a  natural  classification  of  these  organisms.  Thus,  especial  attention 
was  paid  to  the  presence  and  type  of  each  kind  of  spores  (micro-  and 
macroconidia  and  chlamydospores) .  Type  of  color  production  was  found 
to  be  next  in  importance.  Type  of  fructification  and  of  conidiophores, 
size  of  spores,  presence  or  absence  and  kind  of  sclerotia,  and  rate  and 
character  of  colony  growth,  were  also  found  to  be  of  more  or  less  consider- 
able importance  for  differentiation  of  the  species. 

Some  work  has  been  done  on  the  action  of  these  organisms  under 
different  environmental  conditions  and  also  with  respect  to  their  patho- 
genicity. In  regard  to  the  latter  the  following  four  facts  should  be  men- 
tioned : 

1.  Extensive  inoculations  of  potato  plants  with  all  the  Fusaria  pre- 
sented here  yielded  negative  results  and  would  indicate  that  they  are  not 
wilt  producers.* 

2.  Several  series  of  inoculations  of  potato  tubers  showed  (a)  that  a  con- 
siderable number  of  the  Fusaria  can  cause  more  or  less  rapid  decay  of  the 
tubers,  and  (b)  that  most  of  the  Fusaria  readily  produce  rot  only  after  the 
tubers  begin  to  sprout. 

3.  The  commonest  rot-producing  organism,  at  least  in  eastern  United 
States,  is  F.  coeruleum  (Lib.)  Sacc. 

4.  The  inoculations  into  tubers  seem  to  indicate  that  some  species 
widely  different  morphologically  may  act  similarly  pathologically,  and 
that  other  species  very  closely  related  from  the  morphological  standpoint 
differ  very  widely  in  their  pathogenicity. 

The  other  results  of  this  phase  of  the  work  will  be  mentioned  only  in 

3  In  this  study  no  special  attempt  was  made  to  discover  the  perfect  stage  of  any  of  these  organisms. 
At  the  same  time  it  is  to  be  noted  that  under  the  condition  of  the  work  when  a  considerable  number  of 
"  natural  "  as  well  as  "  artificial  "  media  were  used,  none  of  the  Fusaria  produced  a  perfect  stage. 

*  The  writer  does  not  mean  by  this  statement  that  the  Fusaria  actually  never  produce  wilt  of  potatoes, 
because  it  is  possible  that  the  negative  results  were  due  to  lost  virulence  of  the  cultures  used  or  to  some 
other  important  factor  that  escaped  attention. 


FusARiA  OF  Potatoes  101 

those  instances  in  which  different  action  under  different  environment  is  of 
importance  in  identification. 

SOURCE  AND  METHODS  OF  ISOLATION 

Most  of  the  species  of  Fusarium  and  related  organisms  presented  here 
were  isolated  from  potato  tubers  affected  with  dry  or  soft  rot..  A  number 
of  isolations  were  made  also  from  discolored  fibro-vascular  bundles  of 
potato  tubers  and  from  stems  of  wilted  potato  plants.  A  single  organ- 
ism, Fusarium  metacroum  var.  minus,  was  isolated  from  a  spot  on  the 
surface  of  a  half-dead  potato  stem. 

In  a  few  cases  the  isolations  were  made  by  means  of  poured  plate 
dilutions,  but  in  the  majority  of  cases  they  were  made  from  affected  tissues 
of  the  host.  The  affected  part  of  the  host  was  first  thoroughly  wiped 
with  a  piece  of  cheesecloth  moistened  in  0.1  per  cent  solution  of  corrosive 
sublimate,  and  then  the  "skin"  was  peeled  off  just  above  the  affected 
part,  or  the  diseased  part  of  the  plant  was  broken  open  so  that  the  spot 
from  which  the  isolation  was  to  be  made  was  not  touched  even  with 
sterile  utensils.^  Four  or  five  small  fragments  of  diseased  tissue  were 
cut  out  with  a  sterile  scalpel  and  transferred  with  a  sterile  needle  to 
cooled  poured  plates  of  a  suitable  medium.  When  a  rotted  tuber  showed 
a  noticeable  difference,  in  color  or  otherwise,  in  different  regions 
of  the  decayed  part,  a  separate  set  of  plantings  was  made  from 
each  region.  The  actual  isolation  of  more  than  one  Fusarium  from  a 
single  tuber  shows  that  this  precaution  was,  at  least  in  some  cases, 
worth  while. 

Several  days  after  plantings  were  made,  if  any  fungi  were 
present  they  usually  had  made  considerable  growth  and  often  allowed 
a  preliminary  macro-  and  microscopic  comparison  of  the  isolated 
organism  with  any  others  of  the  same  series  of  isolations  or  of  former 
ones. 

In  case  a  fungus  thus  obtained  was  different  in  some  way^  from  the 
others,  two  transfers  into  test  tubes  of  a  suitable  medium  were  made  for 
further  study.     In  order  to  make  a  culture  from  the  start  as  pure  as 

*  Small  instruments  and  glassware  may  be  sterilized  conveniently  by  storing  them  in  a  jar  of  80-per- 
cent alcohol.  When  ready  to  use  the  excess  alcohol  is  burned  off  by  passing  the  instruments  through  a 
flame.     When  so  treated  the  instruments  are  sterile,  perfectly  dry,  and  not  too  hot  for  immediate  use. 

"Rate  and  character  of  growth,  color,  and  type  of  spores  were  at  first  almost  the  only  charactera  on 
which  these  organisms  were  judged. 


102  C.  D.  Sherbakoff 

possible,  these  transfers  were  made  from  the  very  margin  of  the  colony. 
But  if  in  a  colony  there  were  apparently  two  or  more  organisms  growing 
together,  this  method  would  invariably  lead  to  isolation  of  the  rapidly 
growing  one  and  loss  of  the  slower-growing  one.  In  order  to  save  the 
latter  also,  the  plates  with  original  plantings  were  kept  for  a  long  time 
after  the  first  transfers  were  made,  and  now  and  then  dilutions  were 
made  from  the  old  colonies.  In  the  majority  of  cases  this  work  was 
useless,  but  in  two  cases  there  were  isolated  very  slow-growing  fungi  — 
F.  dimermn  var.  Solani  and  F.  mlum  var.  Solani  —  which  otherwise 
would  have  been  missed. 

The  cultures  obtained  by  transfers  from  original  plantings  seemed  to 
be,  and  usually  were,  pure  cultures  from  the  start.  Nevertheless  it  was 
evident  that  some  method  of  obtaining  cultures  from  single  spores  must 
be  employed  before  a  comparative  study  of  the  organism  could  be  profit- 
ably begun. 

In  those  few  instances  in  which  a  culture  did  not  produce  any  spores  for 
a  long  time  and  which  appeared  to  be  a  mixture  of  more  than  one  fungus, 
an  attempt  was  made  to  separate  the  organisms  by  the  mere  planting 
of  a  small  bit  of  the  fungous  growth  in  the  center  of  a  newly  poured  plate. 
In  only  one  case  was  the  result  satisfactory.  This  was  when  a  bit  of 
mixed  growth  of  F.  arcuosporum  and  Raniularia  Magnusiana,  on  being 
planted  in  a  plate,  produced  from  the  start  on  one  side  a  pure  growth  of 
one  fungus  and  on  the  other  side  a  pure  growth  of  the  other  fungus. 
In  all  the  other  cases  a  culture,  if  transferred  into  several  different  media, 
sooner  or  later  always  produced  a  sufficient  number  of  spores;  and  in 
order  to  obtain  a  pure  culture  the  poured-plate  method  of  dilution  was 
invariably  employed. 

Considerable  economy  of  time  and  labor  was  effected  by  placing  a  number 
of  separate  drops  of  sterile  water  in  a  sterile  plate.  By  transferring 
spores  from  drop  to  drop,  a  drop  is  soon  secured  in  which  the  number 
of  spores  is  such  that  a  small  loopful  transferred  to  a  drop  in  another 
plate  will  contain  only  thirty  or  forty  spores.  The  melted  and  properly 
cooled  medium  is  then  poured  into  the  plate,  and  distribution  of  spores 
is  effected  by  giving  the  plate  a  rotary  motion  before  the  medium  has 
hardened. 

The  first  observation  of  the  dilution  plates  was  made  about  a  day  later. 
At  this  time  most  of  the  spores  had  germinated  and  could  be  observed 


FusARiA  OF  Potatoes  103 

from  the  bottom  of  the  plate  with  comparative  ease.  When  a  single 
spore  at  some  distance  from  the  others  was  located,  it  was  marked  with  a 
circle  of  india  ink.  In  this  manner  several  spores  were  marked  and  the 
plate  was  left  for  another  day,  after  which  the  colonies  were  usually  large 
enough  to  be  observed  with  the  unaided  eye.  Transfers  could  then  be 
made  easily  and  surely.  These  transfers  have  been  kept  as  the  stock 
cultures.  The  dilution  plates  from  which  stock  cultures  were  obtained 
were  kept  for  several  weeks  longer,  in  order  to  see  whether  all  the  colonies 
were  alike. 

In  only  three  cases,  after  the  first  dilution,  did  there  appear  to  be  different 
colonies  present  in  the  same  separation  plates.  In  one  of  these  cases  this 
was  the  result  of  a  mixed  growth  of  two  distinct  fungi.  It  is  of  some 
interest  to  note  here  that  the  mixed  culture  appeared  to  be  a  fine  specimen 
of  a  pink  fungus.  On  dilution  it  gave  rise  to  a  brick  red  fungus,  F.  meta- 
croum,  and  a  white  one,  F.  diver sisporum.  In  the  other  two  cases  the 
fungi  obtained  from  the  differently  appearing  colonies  represented  most 
closely  related  organisms  which  never  were  isolated  again,  but  which 
nevertheless  remain  distinct  from  each  other.  Whether  they  represent 
mutations,  fluctuations,  or  mere  chance  coexistence  of  the  two  actually 
different  organiems,  is  a  matter  yet  undecided.  They  are  tentatively 
designated  as  two  different  varieties  —  F.  bullatum  var.  roseuni  and  F. 
arthrosporioides  var.  asporotrichius. 

The  stock  cultures  were  subsequently  repeatedly  rediluted,  and,  as 
was  to  be  expected,  almost  invariably^  every  dilution  plate  showed  all 
the  colonies  from  the  same  stock  culture  to  be  alike. 

As  it  is  not  possible  to  use  a  high-power  objective  with  the  ordinary 
petri  dish,  and  as  single  spores  of  some  of  the  species  are  very  difficult 
to  locate  because  of  their  size  and  lack  of  color,  there  was  always  the 
possibility  that  some  of  the  cultures  vs^hich  seemed  to  be  pure  were  really 
mixtures,  for  it  is  a  well-known  fact  that  the  spores  of  many  fungi  often 
cling  together  tenaciously.  In  order  to  make  absolutely  sure  that  pure 
cultures  were  being  dealt  with,  the  further  precaution  was  observed  in 
1913  of  locating  single  isolated  spores  with  a  high-power  objective  and 

'  Only  two  exceptions  were  observed:  (1)  In  the  case  of  F.  metacroum  var.  minus  among  characteristic 
red  colonies,  there  appeared  one  colorless  colony.  For  a  while  the  absence  of  color  was  a  constant  char- 
acter, but  later  the  color  was  produced  again.  (2)  In  the  case  of  F.  diversisportim  among  colonies  with 
high  aerial  mycelium  there  was  a  colony  almost  without  aerial  mycelium.  In  subsequent  generations  the 
aerial  mycelium  reappeared  almost  to  the  same  extent  as  originally. 


104  C.  D.  Sherbakoff 

securing  cultures  from  them.^  The  cultures  thus  obtained  were  in  all 
respects  similar  to  the  originaKstock  cultures,  thus  confirming  the  relia- 
bilitj^  of  the  poured-plate  dilution. 

CULTURE  MEDIA 

It  is  a  well-known  fact  among  mycologists  that  under  different 
environmental  conditions  many  fungi  vary  considerably  in  their 
macro-  and  microscopic  characters.  One  of  the  most  important 
factors  in  variability  is  the  substratum.  According  to  Thom  (1910), 
certain  characters  in  Penicillia  appear  only  when  the  fungi  are  grown 
on  a  certain  medium.  Other  instances  of  a  similar  nature  might  be 
cited. 

Because  of  this  variability  of  many  fungi  with  variation  in  the  sub- 
stratum, it  seemed  indispensable  in  this  study  of  Fusaria  to  use  a  number  of 
different  media  in  order  to  find  the  extent  of  the  variability  in  the  Fusaria 
and  to  determine,  if  possible,  which  media  could  be  most  profitably 
employed  in  this  kind  of  work. 

The  so-called  "  natural  "  media,  as  well  as  artificial  media,  were  used.^ 
Those  employed  most  extensively  were  potato  tuber  and  stem  plugs,  and 
hard  agars  of  potato,  lima  bean,  and  oat.  For  the  study  of  color  produc- 
tion, from  8  to  10  per  cent  of  sugar  (glucose)  was  added  to  one  of  the 
above  agars,  usually  to  potato  agar.  In  all  other  cases  the  agars  were 
used  without  glucose  or  with  a  small  amount  of  it  (0.5  per  cent).  In  a 
few  instances  the  agars  were  more  or  less  acidified  by  the  addition  of  small 
quantities  of  lactic  or  citric  acid  (from  1  to  3  drops  of  50-per-cent  acid 

8  The  method  employed  was  as  follows:  A  number  of  drops  (from  eight  to  ten)  of  sterilized  potato 
broth  were  placed  on  a  sterile  glass  slide.  Dilution  transfers  were  made  from  drop  to  drop  until  such  a 
dilution  was  secured  that  on  removing  a  small  droplet  on  the  flattened  end  of  a  platinum  needle  it  was 
found  by  microscopic  examination  that  in  many  cases  a  single  spore  could  be  obtained.  From  such  a 
drop  nine  transfers  were  made  to  a  sterile,  but  somewhat  greasy,  cover  glass.  By  placing  the  cover  glass 
over  a  tubular  glass  cell  or  a  van  Tieghem  cell,  each  individual  droplet  could  be  examined  with  a  high- 
power  objective.  Droplets  containing  no  spore  or  more  than  one  spore  were  wiped  oflf  at  once  with  a 
pointed  piece  of  blotting  paper.  In  thus  removing  spore  droplets,  the  spores  also  were  invariably  removed. 
Sterile  water  was  placed  in  the  bottom  of  the  cell  and  the  cover  glass  was  sealed  to  the  cell  with  sterile 
water.  The  cells  were  then  placed  in  a  moist  chamber  for  about  twelve  hours,  and  by  this  time  the  spores 
had  usually  germinated  and  could  be  observed  with  much  greater  ease.  This  observation  was  almost 
indispensable  in  the  case  of  those  species  that  produce  numerous  minute  microconidia,  as  any  such  could 
be  easily  detected  at  this  stage.  Only  two  or  three  droplets  bearing  single  unmistakably  germinating 
spores  were  allowed  to  remain  on  the  covers.  At  the  end  of  twenty-four  hours  more,  the  growth  of  mycelium 
from  the  single  spores  was  usually  sufficient  to  be  seen  with  the  unaided  eye  and  could  be  transferred 
readily  with  a  finely  pointed  needle  to  a  suitable  medium. 

'The  media  used  were:  (1)  Natural  —  potato,  bean,  and  pea  stems;  rye  straw;  canes  of  red  rasp- 
berry; grains  of  rye,  wheat,  oat,  barley,  corn,  and  rice;  corn  meal  and  oatmeal;  whole  potato  tubers  and 
plugs  of  potato  tuber.  (2)  Artificial  —  potato,  hma-bean,  oat,  corn,  and  nutrient  agars  (hard  and  soft, 
from  1  to  3  per  cent  agar,  neutral  and  more  or  less  acidified,  without  and  with  different  amounts  of  glucose). 


FusARiA  OF  Potatoes  105 

to  10  cubic  centimeters  of  the  medium) ;  otherwise  they  were  used  as  they 
were  after  the  process  of  coolving  and  sterihzing.^" 

The  method  of  preparing  all  natural  media  was  very  simple.  It  con- 
sisted in  cutting  suitable  pieces,  tubing,  and  sterilizing  in  an  autoclave 
for  twenty  minutes  at  fifteen  pounds  pressure.  Enough  distilled  water 
was  added  to  the  tubes  to  keep  the  cultures  in  good  growing  condition 
for  from  three  to  four  weeks,  the  exact  amount,  of  course,  depending  on 
the  size  and  succulence  of  the  material  used.  The  decoctions  that  were 
most  commonly  used  were  prepared  in  the  following  ways: 

Potato  decoction. —  Two  hundred  grams  of  peeled  potato  tubers  were 
sliced,  1000  cubic  centimeters  of  distilled  water  was  added,  and  the  material 
was  cooked  for  about  forty  minutes  in  a  double  boiler.  The  clear  liquid 
was  then  decanted  and  the  volume  restored. 

Lima-bean  and  oat  decoctions  were  prepared  by  soaking  100  grams  of 
ground  lima  beans  or  oats  in  1000  cubic  centimeters  of  distilled  water  at 
60°  C,  in  an  incubator  for  an  hour.  The  liquid  was  separated  by  strain- 
ing through  cheesecloth  and  the  volume  was  restored  to  the  original  1000 
cubic  centimeters. 

Corn  meal  decoction  was  prepared  as  described  by  Shear  and  Wood  (1913) ; 
that  is,  from  about  35  to  40  grams  of  corn  meal  were  treated  in  the  same 
way  as  100  grams  of  lima  beans  or  oats  in  the  preceding  case. 

For  the  artificial  media,  to  1000  cubic  centimeters  of  a  decoction  were 
added  agar  (10,  15,  or  30  grams,  these  amounts  corresponding  respectively 
to  soft,  medium,  and  hard  agar)  and  glucose  (0  to  100  grams),  and  the 
whole  was  cooked  in  a  double  boiler  over  a  free  flame  for  an  hour,  or, 
more  exactly,  until  all  the  agar  was  well  dissolved.  The  liquid  was  then 
tubed,  plugged,  and  sterilized  in  the  same  way  as  were  the  natural  media. 

At  the  present  stage  of  this  work,  it  seems  that  all  the  labor  spent  on 
using  so  many  different  media  was  more  or  less  wasted.  It  seems  that 
the  same  results  could  as  well  be  obtained  with  but  a  few  good  media, 
preferably  the  following:  a  hard  oat  agar  (without  glucose),  a  stem  and 
tuber  plug,  and  a  potato  agar  with  about  5  per  cent  of  glucose.  All  other 
media  used  in  the  course  of  this  work  did  not  prove  to  be  of  any  specific 
value,  and  at  the  best  gave  the  same  results  that  were  obtained  with 
those  just  named. 

10  When  an  acid  was  added  to  an  agar  this  was  done  after  the  medium  was  sterilized,  the  medium  then 
being  quickly  cooled.  This  quick  cooling  was  necessary  because  otherwise  an  acidified  agar  often  would  not 
solidify  as  weU  as  it  should. 


106  C.  D.  Sherbakoff 

For  determination  of  the  color  of  the  substratum  and  also  for  study  of  the 
colony  growth,  it  would  perhaps  be  best  to  use  poured  plates  with  about 
10  cubic  centimeters  of  a  clear  agar.  In  this  work  potato  hard  agar  with 
from  5  to  10  per  cent  of  glucose  was  almost  exclusively  used  for  this  pur- 
pose. For  the  study  of  other  characters,  in  most  cases  cultures  were  made 
in  common  test  tubes. 


EFFECT   OF   VARIOUS   MEDIA    ON    DIFFERENT    CHARACTERS    OF   FUSARIA 

In  the  course  of  this  work  it  was  observed,  in  partial  confirmation  of 
the  statement  by  Appel  and  Wollenweber  (1910: 12-23),  that  certain  media 
affect  fungous  growth  more  or  less  characteristically.  A  medium  too 
rich  in  nutrients,  especially  in  glucose,  usually  gives  cultures  with  more  or 
less  abnormal  spores,  the  abnormality  showing  itself  in  a  too  dense  granula- 
tion of  the  protoplasm,  in  more  or  less  considerable  swelling  of  the  spore 
cells,  and  often  in  abnormal  septation,  size,  and  shape. 

Media  rich  in  glucose  usually  increase  the  density  of  color  produced  by 
these  fungi,  and  often  also  change  its  character.  For  example,  a  pink 
fungus,  F.  arcuosporum,  is  turned  to  a  clay-colored  one;  or  the  fungus 
F.  angustum,  which  is  colorless  or  nearly  so,  is  turned  to  a  more  or  less 
bright  purplish-vinaceous  one;  and  so  forth. 

Excess  of  water  in  a  medium  usually  leads  to  comparatively  quick 
degeneration  (self-digestion  ?)  of  the  spores,  and,  in  general,  to  a  shortened 
duration  of  the  vitality  of  the  culture.  Its  presence,  at  least  in  case  of  a 
soft  agar  as  compared  with  a  hard  agar,  is  usually  unfavorable  for  the 
normal  development  of  aerial  mycelium. 

A  medium  comparatively  poor  in  nutrients,  such  as  corn  meal  agar, 
seldom  gives  rise  to  sclerotia  and  plectenchymic  sporodochia;  but  in 
a  way  it  is  a  good  medium  for  the  study  of  chlamydospores,  which  are 
produced  here  more  or  less  freely  and  stand  out  more  clearly  than  in  other 
media. 

Whole  potato  tubers  (steamed)  often  are  most  favorable  for  production 
of  large  sporodochia;  this  medium,  and  also  potato  tuber  plugs  (also 
steamed),  show  the  largest  sclerotia.^^ 

An  agar,  especially  such  a  one  as  oat  hard  agar,  often  gives  all  the  forms 

"  See  also  Wollenweber  (1913  a:  25). 


FusARiA  OF  Potatoes  107 

of  fructification  for  these  fungi,  with  "  normal  "  spores  and  more  or  less 
typical  and  brilliant  color  production.^'- 

On  the  plugs  made  from  stems  of  different  plants,  spore  production  seems 
to  be  normal. ^^  The  spores  are  of  typical  and  comparatively  uniform  shape, 
septation,  and  size,  without  too  dense  granulation  of  the  protoplasm, 
and  with  a  long  duration  of  vitality.  It  often  is  found,  however,  that  on 
such  media  spores  are  less  normal  than,  for  instance,  on  a  hard  agar. 

Presence  of  the  epidermis  on  the  stem  and  tuber  plugs  seems  to  favor 
production  of  fewer  but  better  developed  sporodochia,"  and  often  lessens 
development  of  aerial  mycelium. 

Certain  media,  such  as  boiled  rice,  give  a  color  that  is  typical  for  certain 
related  Fusaria. 

EFFECT   OF   LIGHT  AND   OF   REACTION   OF   THE   MEDIUM   ON    DIFFERENT 
CHARACTERS  OF  FUSARIA 

As  was  stated  in  the  introduction,  very  little  systematic  work  has  been 
done  on  the  ecology  of  the  Fusaria.  The  few  things  which  have  been 
found  by  other  workers  and  by  the  writer,  and  which  have  some  value 
in  the  determination  of  these  fungi,  may  be  summed  up  brieflj^  as  follows: 

1,  A  diffuse  daylight  may  affect  color  production  considerably  (Smith 
and  Swingle,  1904:48^9),  but  in  most  cases  the  effect  is  only  slight  or 
there  is  almost  none.  It  usually  intensifies  the  colors  produced  by  these 
fungi.  A  very  strong  light  often  makes  the  colors  somewhat  duller,  espe- 
cially in  the  case  of  Fusaria  producing  bright  red  colors,  these  being  turned 
toward  brown  hues.  No  noticeable  effect  of  the  light  was  observed  on 
other  characters  of  these  fungi,  although  Appel  and  Wollenweber  are  of 
the  opinion  that  the  spores  are  of  a  more  normal  type  in  the  light  than 
in  the  dark. 

2.  According  to  Appel  and  Wollenweber  the  reaction  of  the  medium 
has  an  especially  noticeable  effect  on  blue  colors,  which  can  appear  only 
in  a  medium  of  neutral  or  rather  alkaline  reaction.  The  blue  color  in  a 
medium  of  an  acid  reaction  will  appear  as  orange.   True  red  colors  remain 

'2  This  observation  is  apparently  in  some  contradiction  to  the  observations  of  Appel  and  Wollenweber 
(1910:12-13),  but  indeed  it  is  not  so;  because,  judging  by  the  "  artificial  "  media  actually  used  by  them, 
their  observation  of  unfitness  of  such  media  for  study  of  "  normal  "  growth  of  the  Fusaria  was  based  on 
"  soft  "  agars  too  rich  in  sugar.     The  writer  also  found  that  such  agars  produced  abnormal  growth. 

"This  was  observed  first  by  Appel  and  Wollenweber  (1910),  and  on  this  okservation  mainly  they  con- 
cluded that  the  only  way  to  study  the  Fusaria  properly  is  to  study  them  on  such  "  natural  "  media. 

"This  was  first  observed  by  Appel  and  Wollenweber  (1910). 


108  C.  D.  Sherbakoff 

red  even  in- a  medium  of  an  alkaline  reaction.  The  observations  of  the 
writer,  so  far  as  they  go,  are  in  full  agreement  with  the  above  statements; 
to  which  it  may  be  added  that  certain  fungi  which  in  a  neutral  medium 
produce  a  grayish  white  aerial  mycelium  {F.  sclerotioides) ,  in  the  same 
medium  strongly  acidified  (0.4  per  cent  by  weight  of  citric  acid)  produce 
an  aerial  mycelium  of  a  pink-vinaceous  shade. '^ 

It  was  observed  also  that  acidity  of  the  medium  lowers  the  rate  of  the 
fungous  growth  and  makes  zonation  of  the  colony  more  prominent  and 
closer.  The  retardation  of  the  growth  depends  on  the  kind  of  acid  (see 
also  Smith  and  Swingle,  1904:42,  48)  and  its  concentration;  different 
Fusaria  are  not  affected  in  the  same  degree,  some  tolerating  more  acid 
than  others  (see  also  Lewis,  1913:238). 

THE    GENUS    FUSARIUM 

Appel  and  Wollenweber  (1910:4-12,  23-61)  present  a  very  detailed, 
critical  study  of  the  genus,  with  the  following  list  of  synonyms: 
Atractiurn  Link  pr.  p.  (1809) 
Fusidium  Link  pr.  p.  (1816  and  1825) 
Fusisporium  Link  (1824) 
Selenosporium  Corda  (1837) 
Fusoma  Corda  (1837) 
Pionnotes  Fries  (1849) 

The  description  of  the  genus  Fusarium  given  by  these  investigators, 
when  other  data  presented  by  them  are  also  taken  into  consideration 
and  using  the  terminology  of  Lindau  (1905,  1908-1909),  may  be  stated 
in  brief  as  follows: 

Hyphomycetes  of  Mucedinaceae-Hyalophragmiae,  Hyalostilbacese-Phrag- 
mosporse,  and  Tuberculariacese-Mucedinese-Phragmosporse  groups,  with 
smooth,  not  appendiculate,  mostly  sickle-shaped,  acrogenous,  noncatenu- 
late  conidia. 

The  genus  as  delimited  by  these  authors  was  to  include  also  forms 
such  as  F.  dydimum  and  F.  Willkommi,  with  cylindrical,  one-septate  spores, 
and  bacilliform,  one-  to  five-septate  spores. 

The  writer  has  not  sufficient  material  on  hand  to  warrant  any  change 
in  the  above  characterization  of  the  genus;  but  in  the  course  of  this  work, 

15  The  medium  used  in  the  instance  cited  was  potato  hard  agar  plus  5  per  cent  of  glucose.  The  cultures 
were  made  in  petri  dishes. 


FusARiA  OF  Potatoes  109 

a  true  Fusarium  never  was  observed  which  would  produce  a  typical 
coremium^^  or  a  typical  pionnotes,^^  that  is,  the  two  fruiting  forms  on 
the  basis  of  which  the  genera  Atractium  and  Pionnotes  were  founded 
by  their  authors  and  which  are  now  reduced  to  synonymy  by  Appel 
and  Wollenweber  because  these  investigators  find  in  the  Fusaria  certain 
structures  resembling  these  two  forms. 

That  one  of  these  forms,  Pionnotes,  is  a  distinct  form,  and  that  its 
characters  can  be  used  as  a  basis  in  a  classification  of  Fusarium-like 
organisms,  has  been  shown  lately  by  Wollenweber.  After  citing  Fusarium 
{Pionnotes)  udum  and  its  variety  as  instances  of  the  Fusaria  without 
"  Fusszelle,"  he  (1913c:  206)  says:  "  Beilaufig  bemerkt,  bilden  solche 
Fusarien  zusammen  mit  F.  aquaeductum  eine  gute  Section  der  Gattung, 
die  ich  Eupionnotes  nenne  wegen  des  Ubergewrichtes  dieser  Sporenver- 
lagerung." 

There  is  very  little  doubt  that  a  true  coremial  form  of  fructification 
is  quite  distinct,  and  does  not  occur  in  the  species  of  Fusarium  observed 
by  the  writer. 

With  respect  to  the  present  status  of  the  genus  Fusarium,  some  recent 
changes  must  be  considered  here.  Wollenweber  (1913  a: 33)  transferred 
from  the  genus  Fusarium  to  the  genus  Ramularia  all  forms  with  conidia 
of  F.dydimum  type  when  chlamydospores  are  present.'^  The  same  author 
(1913  c:225),  somewhat  later,  also  excluded  from  the  genus  Fusarium 
forms  with  conidia  of  the  type  of  F.  WiUkommi  and  transferred  them 
into  a  new  genus,  Cylindrocarpon,'^  established  for  this  purpose.  Thus, 
in  fact,  all  forms  having  cylindrical  conidia  or  conidia  with  rounded  ends 
are  excluded  by  Wollenweber  (1913  c:  239)  from  the  genus  Fusarium. 
The  genus  Sepedonium  Link  (1809),  according  to  Wollenweber  (1913  c: 
200),  is  only  a  chlamydosporial  stage  of  Fusarium  orthoceras. 

It  appears,  then,  from  the  study  of  the  Fusarium-like  organisms  of 
potatoes  (which,  on  the  whole,  represent  a  great  diversity  of  forms)  and 
also  from  a  careful  survey  of  the  genus  Fusarium  as  it  stands  in  literature, 
that  the  following  characters  are  of  generic  value: 

16  The  terminology  which  is  used  here  is  the  same  as  that  of  Lindau. 

1' Only  one  Fusarium-like  organism  was  isolated  from  potatoes  which  produces  a  fruiting  layer  very 
similar  to  a  pionnotes  {F.  udum  var.  Solani) ,  but  it  is  very  distinct  from  all  the  other  Fusaria  and  can  be 
used  rather  to  support  than  to  disprove  the  above  statement. 

18  In  those  cases  in  which  chlamydospores  are  not  present,  Wollenweber  says  the  fungi  have  a  perithecial 
stage  of  the  genus  MycosphEerella. 

19  This  genus  is  to  include  only  those  forms  for  which  a  perithecial  stage  has  not  yet  been  found. 
F.  WiUkommi  has  been  connected  with  Nectria  galligena. 


110  C.  D.  Sherbakoff 

1.  Color  of  conidia  and  mycelium,  never  of  a  plain  gray  or  black  color 
but  mostly  of  various  brilliant  hues. 

2.  Conidia  dorsiventral,^^  attenuate,  pedicellate,"^  not  appendiculate, 
smooth,  normally  not  constricted  at  the  septa,  distinctly  three-  (or  more) 
septate,^^  acrogenous,  not  in  chains.-^ 

3.  Conidiophores  with  single  to  irregularly  whorled  branches,  never 
truly  dichotomous  nor  of  a  strictly  penicilla  e  or  verticillate  type.  The 
conidiophores,  through  many  times  repeated  branching  or  also  by  growing 
side  by  side  with  other  conidiophores,  typically  give  rise  to  macroscopically 
observable,  dense  tufts  of  conidiophores  covered  more  or  less  deeply 
with  a  somewhat  slimy  mass  of  spores.  Such  fruiting  bodies,  tuberculate 
in  form  (sporodochia),""*  may  be  with  or  without  a  plectenchymic  (=pseudo- 
parenchymic),  flat  or  wartlike  base,  without  any  differentiated  enclosure. 

4.  Chlamydospores  (endogenous,  double-walled,  resting  bodies)  terminal 
and  intercalary,  or  only  intercalary,^^  or  none,  and  produced  both  by 
mycelium  and  by  spores. 

5.  Mycelium  composed  of  hyphse  which  are  always  distinctly,  but 
not  closely,  septate,  and  irregularly,  never  dichotomously,  branched,  the 
secondary  branches  usually  thinner  than  the  primary  ones;  protoplasmic 
content  of  the  mycelium  for  the  greater  part  plainly  present  and  usually 
distinctly  vacuolate.  The  rate  of  growth  in  artificial  media,  when  com- 
pared with  the  Fusarium-like  organisms  studied,  is  comparatively  high. 

It  must  be  added  here,  as  a  general  remark  to  the  characteristics  of  the 
genus  Fusarium  given  above,  that  in  this  case,  as  well  as  in  any  other 
attempts  at  classification  of  natural  phenomena,  the  boundaries  laid 
down  for  separation  of  one  group  of  phenomena  from  all  the  rest  have 
only  a  relative  value.  Thus  an  organism  may  deviate  ^^  in  a  greater 
or  less  degree  in  one  or  a  few  of  the  characters  given  above,  and  yet,  so 

21)  This  term  is  ussd  by  Appel  and  Wollenweber  (1910). 

2'  This  term  is  used  by  Wollenweber  (1913  c).     See  liis  key  on  page  219  of  reference  cited. 

~  Fusaria-like  organisms  with  one-septate  conidia  are  rare.  Two  such  organisms  were  isolated  from 
potatoes,  and  from  over  one  hundred  and  sixty  Fu.saria  recorded  by  Lindau  (1908-1909:517-588)  only 
seven  are  definitely  stated  to  have  one-septate  conidia;  and  of  these  seven  at  least  two  are  undoubtedly 
not  Fusaria  if  the  changes  made  in  this  genus  by  Wollenweber  are  considered. 

23  Microconidia  may  be  produced  in  chains.  This  is  true  in  case  of  certain  Fusaria  of  corn  and  of 
coniferous  seedlings.  (See  Sheldon,  J.  L.  A  corn  mold  [Fusarium  moniliforme  n.  sp.].  Nebraska  Agr. 
Exp.  Sta.     Kept.  17:  23-32,  fig.  1.     1904.) 

-*  The  termiml  j^v'  used  here  is  the  same  as  that  used  by  Wollenweber  (1913  a  :  24,  footnote). 

2^  The  only  Fusariurn-Uke  fungus  isolated  by  the  writer  which  has  only  terminal  chlamydospores  seemi 
not  to  be  a  typical  Fusarium.       (See  F.  cuneiforme,  key  and  description.) 

™  Of  course  a  true  Fusarium,  evidently,  in  no  case  can  be  of  a  plain  gray  or  black  color  (in  mycehum 
and  conidia  as  well),  or  have  non-septateor  cylindrical  macroconidia  with  both  ends  rounded.  (In  regard 
to  the  macro-  and  microconidia,  see  page  116.)  Its  conidia  cannot  be  appendiculate  nor  its  conidiophores 
of  a  true  verticillate  or  any  other  specifically  peculiar  type. 


FusARiA  OF  Potatoes  111 

to  speak,  be  a  good  Fusarium  provided  all  other  ch  racters  of  this  genus 
are  well  expressed  by  the  organism. 

variability  in  the  FUSARIA 

Many  of  the  morphological  and  physiological  characters  of  the  Fusaria 
show  marked  variability,  and  at  first  seem  to  be  of  such  a  nature  as  to 
discourage  any  attempt  to  treat  these  fungi  on  a  morphological  basis. 
Thus  Smith  and  Swingle  (1904:27),  in  regard  to  their  F.  oxysporwn,  say: 

" This  fungus  showed  a  number  of  very  striking  variations.     For  this 

reason  it  is  impossible  to  give  a  general  description  that  will  hold  uni- 
versally." And  after  quoting  descriptions  of  eleven  old  species  of  Fusarium 
from  potatoes,  the  authors  conclude  as  follows  (1904:51) :  "Judged  by  the 
above  descriptions,  we  have  had  a  half  dozen  or  more  species  of  Fusarium 
in  our  culture  tubes,  some  of  them  'new  species,'  and  yet  all  were  the 
product  of  a  single  spore.  This  does  not  mean  that  there  have  been  in 
our  cultures  any  very  wonderful  transmutations  of  one  thing  into  another, 
but  only  that  organisms  respond  to  their  environment,  and  that  '  species 
descriptions '  of  the  kind  cited  have  not  taken  this  fact  into  consideration, 
and  consequently  are  worthless  for  scientific  purposes.  This  is  not  a  new 
idea,  but  it  is  a  fact  to  which  the  attention  of  systematic  mycologists 
might  be  directed  profitably  at  frequent  intervals." 

Sometimes  variability,  for  example  in  the  type  of  conidia,  is  so  great 
that  a  student  gives  up  hope  of  determining  the  actual  type.  Thus 
Wilcox,  Link,  and  Pool  (1913:24)  conclude  their  discussion  on  the  form 
of  the  conidia  produced  by  their  fungus^^  as  follows:  "  All  sorts  of  stages 
are  shown  in  the  plate,  so  that  each  one  can  judge  for  himself,  as  it  is 
possible  that  one  who  has  studied  a  great  number  of  species  of  Fusarium 
will  be  able  to  pick  out  the  characteristic  form  which  can  be  set  aside  for 
this  particular  species." 

A  great  number  of  instances  of  variability  in  this  group  also  could  be 
cited  easily  from  the  species  presented  in  this  paper.  But  it  will  suffice 
to  state  here  only  those  instances  of  variability  which  are,  perhaps,  most 
important  and  more  or  less  common: 

1.  The  type  of  the  conidium  varies  in  many  Fusaria  from  micro-  to 

-'F.  luberivorum  Wilcox  and  Link,  whiich  according  to  WoUenweber  (1913  c  :  206)  is  identical  with 
F.  tricholhecioides  Wr. 


112  C.  D.  Sherbakoff 

macroconidia,  and  both  sometimes  are  of  a  very  diverse  type  even  within 
themselves.     (See  F.  diver sispor urn.) 

2.  Conidiophores  often  vary  from  mere  minute  projections  on  the  side 
of  a  hyphal  tliread  to  a  complex  dendroid  structure  often  of  a  size  observable 
macroscopically. 

3.  In  the  Fusaria  for  which  production  of  sporodochia,  plectenchymic 
stromata,  or  sclerotia  is  typical,  it  sometimes  happens  that  they  are  not 
p  oduced  even  under  apparently  favorable  conditions.  These  structures 
may  vary  in  size,  numl^er,  and  form. 

4.  The  presence  or  absence  of  color  is  an  especially  variable  character. 
Changes  in  type  of  color  may  occur,  but  such  changes  are  only  apparent 
and  in  all  known  cases  can  be  explained  on  the  basis  of  the  difference 
in  the  reaction  of  the  medium  (certain  orange-red  colors  in  acid  become 
blue  in  an  alkaline  medium),  or,  when  a  typical  color  is  a  compound  one, 
the  change  may  be  due  to  the  preponderance  of  one  or  another  of  its 
elementary  colors. 

5.  Extent  of  the  development  of  aerial  mycelium,  zonation,  rate  of 
growth,  and  character  of  the  margin  of  the  colony,  may  also  vary  to  a 
considerable  extent. 

6.  Especially  great  variation  may  take  place  in  the  relative  production 
of  the  different  types  of  conidia  and  chlamydospores. 

It  might  appear  at  first  glance  that  the  variation  of  these  fungi  is  so 
great  as  to  leave  no  firm  ground  for  morphological  treatment  of  the  group. 
And  yet  the  actual  situation  is  far  from  being  so  hopeless.  First  of  all, 
the  great  majority  of  the  variations  mentioned  above  occur,  as  did  those 
observed  by  Smith  and  Swingle  (1904:59),  under  different  environmental 
conditions;  while  the  variability  under  identical  conditions  usually  (see 
also  Lewis  1913:225)  is  very  slight.  Secondly,  the  cases  of  variability 
cited  above  are  primarily  cases  of  variation  between  presence  and  absence 
of  certain  characters  —  which  is,  after  all,  of  no  great  importance,  because 
when  a  certain  character  is  present  Jt  is  always  peculiar  to  a  specific  type 
of  organism  and  thus  this  organism  can  be  separated  from  others.  Then 
there  are  certain  Fusaria  which  under  almost  any  but  extreme  environ- 
mental condition  remain  nearly  the  same  throughout  (as  F.  udum  var. 
Solatii  and  F.  cuneiforme).  And  finally,  the  most  important  character 
in  the  classification  of  these  fungi  —  the  type  and  the  shape  of  the  conidia 


FusARiA  OF  Potatoes  113 

—  is  after  all  sufficiently  stable  to  be  used  safely  in  a  morphological 
treatment.  Even  the  size  of  conidia,  when  a  sufficient  number  of  measure- 
ments is  made  and  averaged  and  when  only  conidia  of  the  same  type  are 
compared,  is  of  rather  surprising  uniformity  and  stability.  It  is  believed 
that  every  one  will  agree  with  these  statements  after  an  examination  of 
the  data  presented  here  in  the  descriptions  of  species. 

That  Fusaria  can  be  separated  on  a  strictly  morphological  basis  was 
first  definitely  demonstrated  by  Appel  and  Wollenweber. 

relative  taxonomic  importance  of  different  characters 

Usually  the  particular  organism  and  the  prominence  and  stability  of 
a  given  character  determines  the  relative  importance  of  characters  in 
classification.  Thus,  in  certain  cases  septation  of  conidia  may  be  con- 
sidered as  the  important  character.  For  instance,  in  the  case  of  F.  dimerum 
and  F.  affine,  this  character  distinguishes  these  two  fungi  at  once  from 
all  the  other  Fusaria,  while  in  most  other  cases  it  is  not  of  such  importance. 
Presence  of  a  continuous  slimy  layer  of  spores  is  the  important  character 
in  the  case  of  F.  uduni  var.  Solani  where  this  type  of  fructification  is 
especially  prominent.  Type  of  microconidia,  when  they  are  of  typical 
occurrence  and  especially  when  they  are  of  a  peculiar  type,  as  in  the  case 
of  F.  sporotrichioides,  is  also  a  most  important  character.  Type  of 
chlamydospores  is  an  important  character  in  general  for  dividing  the 
whole  genus  into  sections,  but  it  usually  has  no  specific  value;  and  yet 
there  is  a  fungus,  F.  cuneiforme,  which  can  be  set  off  from  all  the  rest 
because  of  its  terminal  unicellular  chlamydospores.  Color  may  vary 
considerably,  but  on  the  whole  its  type  is  stable  enough  to  be  of  con- 
siderable help  in  dividing  Fusaria  into  sections,  and  sharp  contrasts  in 
color  can  often  be  used  for  specific  differentiation. 

In  general  the  most  useful  and  evidently  sure  basis  for  a  natural  classi- 
fication of  this  group  is  the  shape  of  the  macroconidia.-^  Their  dorsi- 
ventrality,  the  form  of  their  apex  and  their  basal  cell,  and  their  septation, 
and  also  their  size,  when  properly  used,  are  of  considerable  service  in  separa- 
tion of  species.  The  actual  working  value  of  each  character  can  be  seen 
from  the  keys. 

2'  Appel  and  Wollenweber  (1910  :  34)  and  Wollenweber  (1913  a :  2G)  came  to  thia  conclusion  long  before 
the  writer.     See  also  Lewis  (1913  :  225). 


114  C.  D.  Sherbakoff 

FORMS    OF    FRUCTIFICATION    IN    PURE    CULTURES 

Spores 
The  spores  in  the  genus  Fusarium  are  of  two  kinds :  conidia,  or  acrog- 
enous  spores,  and  chlamydospores,  or  endogenous  resting  bodies.     The 
conidia  in  turn  may  be  divided  into  two  more  or  less  distinct  types: 

(1)  macroconidia,    sickle-shaped,    three-    or  more    septate    spores;    and 

(2)  microconidia,  oval,  non-  or  only  one-  or  two-septate  spores. 

Before  the  appearance  of  Appel  and  Wollenweber's  work  (1910)  the 
existence  of  micro-  and  macroconidia  as  two  distinct  types  was  more 
or  less  generally  accepted,  but  in  that  work  it  was  concluded  (page  29) 
that  there  is  only  one  type  of  conidia.  The  latter  view  is,  of  course, 
correct  so  far  as  the  genetic  relationship  between  micro-  and  macroconidia 
goes.  Nevertheless,  the  typical  presence  of  microconidia  in  certain  closely 
related  Fusaria  and  their  typical  absence  in  others  is  characteristic. 
Besides,  whenever  they  are  present  they  have  a  comparatively  constant 
and  often  peculiar  type  of  their  own.  Thus,  they  can  be  used  as  a  good 
natural  basis  for  classification  of  these  fungi,  and  for  that  reason  must 
be  considered  as  a  type  separate  from  macroconidia. 

In  this  paper  the  term  microconidia  is  applied  to  all  nonseptate,  and  seldom 
to  one-  and  even  to  two-  or  three-septate,  conidia  of  a  different  shape  from 
that  of  the  macroconidia,  which  are  sickle-shaped  and  usually  three-  or  more 
septate.     Different  forms  of  macroconidia  are  shown  in  figure  1  (page  112). 

Chlamydospores  may  be  borne  on  the  ends  of  special  lateral  branches 
of  the  mycelium  (terminal  chlamydospores),  or  they  may  be  intercalary. 
They  often  are  produced  in  the  ends  of  the  conidiophores,  in  the  conidia 
or  in  the  ends  of  special  branches  from  the  conidia.  The  chlamydospores 
are  single,  in  short  to  long  chains  or  in  more  or  less  large  clusters.  They 
are  of  common,  though  not  of  general,  occurrence,  and  in  a  number  of 
Fusaria  both  terminal  and  intercalary  chlamydospores  are  present;  in 
some  others  there  are  only  terminal,  and  in  still  others  only  intercalary 
chlamydospores  have  been  observed.  A  number  of  Fusaria  evidently 
have  no  true  chlamydospores;  they  may  possess  structures  with  dense 
content,  but  these  structures  are  not  thick,  double-walled  bodies. 

Forms  of  fructification 
Sometimes,    as   in   the    case   of   the   conidia   on    aerial   mycelium    of 
7^.  trichothecioides,  and  also  in  the  sporotrichial  form  of  F.  sporotrichioides, 


FusARiA  OF  Potatoes  115 

the  conidia  are  borne  singly  and  remain  thus  in  the  form  of  a  powder. 
Usually,  however,  they  adhere  to  the  tips  of  conidiophores  for  a  time, 
forming  balls  of  variable  size.  This  may  be  the  case  with  microconidia 
as  well  as  with  macroconidia.  In  certain  Fusaria,  such  as  F.  cuneiforme, 
and  in  all  members  of  the  section  Martiella,  these  balls  of  conidia  are 
especially  prominent;  but  they  are  very  common  also  in  the  other  Fusaria 
and  therefore  cannot  be  used  for  specific  differentiation. 

When  there  is  no  room  for  old  conidia  to  be  pushed  aside  —  that  is, 
when  the  fruiting  branches  are  very  numerous  and  close  together  — 
a  considerable  and  continuous  mass  of  spores  results;  these,  when  the  air 
is  moist,  form  a  roundish,  wartlike  heap  of  spores,  which,  with  the 
conidiophores  producing  them,  is  known  as  a  sporodochium.  When 
the  air  is  comparatively  dry,  the  spores  are  pushed  up  in  more  or  less 
curled,  long,  tendril-like  columns.  This  is  often  observed  especially 
in  many  cultures  on  sterilized  canes  of  red  raspberry  and  in  stem  plugs 
of  other  plants. 

Often  small  sporodochia  are  produced  on  and  strewn  all  over  the  aerial 
mycelium,  producing  a  picture  very  characteristic  for  F.  subulatum  and 
some  other  Fusaria.  In  other  cases  minute  and  numerous  sporodochia 
are  produced  very  close  to  or  on  the  surface  of  the  substratum,  and  when 
these  minute  sporodochia  are  very  numerous  they  form  a  nearly  con- 
tinuous, slimy  layer  of  conidia.  The  fructification  then  resembles  a 
pionnotes  and  is  called  here  pseudopionnotes.  In  one  case  a  seemingly 
true  pionnotes^^  —  that  is,  a  thick,  continuous,  slimy  layer  of  spores  — 
was  observed  (in  F.  udum  var.  Solani).  A  pseudopionnotes  may  be 
produced  under  aerial  mycelium  which  may  more  or  less  mask  its  macro- 
scopic appearance,  as  in  the  case  of  several  Fusaria  of  the  section  Elegans; 
but  in  certain  cases  there  is  no  aerial  mycelium  over  it,  and  the  pseudopion- 
notes remains  fully  exposed  and  characteristic  for  certain  species.  (See 
F.  metacroum,  F.  falcatum,  and  F.  discolor  var.  sulphureum.) 

Mycelial  threads  in  many  Fusaria  often  run  parallel  and  anastomose 
more  or  less  closely,  thus  producing  a  ropelike  structure  which  may  come 
up  into  the  air  in  an  irregular  fashion  and  which  also  may  bear  more 
or  less  abundant  conidia  produced  on  side  branches.  These  ropelike 
structures  then  resemble  coremia,  which  are  columnar  fruiting  bodies, 
typical  of  the  family  Stilbaceae.  No  true  coremia  wore  observed  in 
any  of  the  Fusaria  presented  here. 

29  The  definition  is  taken  from  Lindau  (1908-1909 :  509). 


116  C.  D.  Sherbakoff 

A  stroma,  in  the  sense  employed  here,^*'  is  tlie  fungous  layer  on  which 
aerial  structures  (aerial  mycelium,  conidiophores,  and  spores)  are  pro- 
duced. The  stroma  may  consist  of  more  or  less  loose  hyphse,  or  it  may 
form  a  dense  pseudoparenchymic  (plectenchymic),  continuous  sheet, 
fleck,  or  prominent  wart.  There  are  often  produced  also  roundish,  more 
or  less  wrinkled,  often  shiny,  bodies,  resembling  true  sclerotia.  They 
are  of  a  dark  blue  color,  and  among  the  Fusaria  studied  in  the  course 
of  this  work  they  were  observed  only  in  certain  species  of  the  section 
Elegans;  though  according  to  Wolhniweber  (1913  a: 32)  they  are  very 
common  also  in  the  section  Roseum,  and  are  characteristic  for  one  species, 
F.  sclerotium  Wr.j  of  the  section  Gibbosum. 

METHOD    OF   STUDY   AND    PRESENTATION 

The  method  actually  employed  in  this  work  consisted  in  the  cultivation 
of  pedigreed  strains  of  the  various  organisms  on  various  natural  and 
artificial  media.  Almost  without  exception,  all  the  strains  were  trans- 
ferred to  a  new  medium  on  the  same  day  and  the  whole  set  of  cultures 
was  kept  under  the  same  environmental  conditions.  In  all  important 
cases  duplicate  cultures  were  employed.  For  the  inoculum,  as  far  as 
possible,  similar  material  was  used  —  that  is,  only  mature  spores  or 
only  aerial  or  only  submerged  mycelium.  The  importance  of  the  same 
environmental  conditions  for  a  comparative  study  is  evident.  It  applies 
equally  as  well  to  the  kind  of  inocula  used,  as  it  was  found^^  that  often 
an  inoculation  made  with  spores  tends  to  better  spore  production,  and 
an  inoculation  with  mycelium  often  results  mainly,  at  any  rate  at  first, 
in  the  production  of  mycelium. 

In  order  to  bring  all  cultures  to  the  same  stage  of  maturity  and  also 
to  assure  their  purity,  dilutions  in  poured  plates  were  made  again  and 
again  for  the  entire  set  of  the  Fusaria  (of  isolations  made  by  the  writer, 
as  well  as  of  the  organisms  obtained  in  culture  from  other  sources),  and 
then  new  transfers  were  made  from  colonies  about  two  days  old  pro- 
duced in  the  plates. 

In  the  macroscopical  examination  of  the  culture,  special  attention  was 
given  to  the  presence  or  the  absence,  and  the  character,  of  aerial  mycelium; 
to  the  kind  of  fructification  layer  (pionnotes-like,  sporodochial,  and  so 
forth);  to  the  color  of  spores,  of  aerial  and  submerged  mycelium,  and  of 

3°  A  slightly  different  definition  of  stroma  is  given  by  Wollenweber  (1913  a:  24,  footnote). 
"  See  Appel  and  Wollenweber  (1910  :  13),  and  also  Lewis  (1913  :  209).     The  same  was  frequently  found 
to  be  the  case  also  in  the  course  of  this  work. 


FusARiA  OF  Potatoes  117 

substratum;  and  to  the  production  of  special  structures  such  as  plecten- 
chymic  stromata  and  sclerotia. 

In  the  microscopical  study,  the  different  types  of  conidia,  chlamydo- 
spores,  and  conidiophores  received  special  attention.  The  observations 
were  recorded  by  means  of  camera  lucida  drawings^^  ^nd  necessary 
measurements. 

When  measurements  were  of  any  importance,^^  ten  conidia  (or  chlamydo- 
spores)  were  measured  and  only  the  average  and  the  extremes  of  these 
measurements  were  recorded.  In  cases  of  special  variability  of  the 
material,  recdl-ds  were  made  of  fifteen  or  twenty  spores  of  each  important 
type  of  septation  and  shape. 

In  making  camera  lucida  drawings,  care  was  taken  to  picture  the  apical 
and  the  basal  ends  of  the  conidia  with  the  utmost  accuracy;  every  kind 
of  conidium  occurring  in  a  culture  was  drawn,  but  the  typical  and  the 
exceptional  cases,  as  they  appeared,  were  marked  off. 

As  a  rule,  measurements  and  drawings  usually  were  made  of  the  conidia 
taken  from  sporodochial  or  pionnotes-like  masses  of  them,  because  such 
conidia  on  the  whole  are  more  uniform  and  typical  for  a  given  organism. 
Here  it  should  be  noted  that  for  the  measurements  and  drawings  it  is 
highly  important,  at  least  in  case  of  very  closely  related  organisms,  to 
use  material  analogous  in  all  respects  —  age,  type  of  fructification,  and 
environmental  condition. 

The  fungi  were  studied,  not  only  on  different  media,  but  also  at  different 
stages  of  their  growth.  The  latter  factor  is  almost  as  important  as  the 
former,  because  in  certain  cases,  as  in  F.  angustum,  conidia  in  the  best 
condition  (most  regular,  and  so  forth)  were  observed  when  the  cultures 
were  very  young.  Some  characters,  however,  become  manifest  only 
after  a  culture  has  reached  a  certain  stage  of  maturity.  This  is  often  the 
case  with  chlamydospores  and  color  production.  Sclerotia  often  appear 
in  comparatively  old  cultures  and  continue  to  grow  for  some  time. 

The  presentation  of  the  species  of  Fusarium  is  based  on  the  following 
main  principles: 

All  drawings  (with  only  a  few  exceptions)  are  intentionally  made  to 
the  same  scale  as  those  of  Appel  and  Wollenweber  —  thus  far  the  one 

32  AH  drawings  were  made  from  living  material  mounted  in  water,  and,  with  a  few  exceptions,  with  an 
oil  immersion  lens.  In  order  to  prevent  movement  of  the  spores  in  water,  it  is  necessary  first  to  use  just 
enough  water  to  keep  air  from  underneath  the  cover  glass,  and  then  to  spread  around  the  cover  glass  some 
oily  substance,  as  cedar  oil,  which  does  not  dissolve  in  water  and  which  does  not  dry  out  quickly. 

^  A  number  of  fields  should  be  examined  before  measuring  in  order  to  see  the  prevailing  type,  and  then 
measurements  of  the  conidia  of  the  prevailing  type  should  be  taken.  This  leaves  much  to  personal  inter- 
pretation, but  otherwise  it  would  be  necessary  to  take  many  more  measurements. 


118  C.  D.  Sherbakoff 

fundamental  work  on  this  subject^*  —  so  that  comparison  can  be  made 
easily.  The  drawings  represent  all  types  of  conidia,  abnormal  ones 
included,  so  that  no  one  may  be  misled  by  types  actually  observed  by  him 
and  by  those  given  here.  This  might  easily  be  the  case  if  only  normal 
material  were  presented,  because  our  understanding  of  what  is  normal  is 
very  relative,  is  often  too  broad,  and  seldom  corresponds  to  the  things 
as  they  are.  The  particular  forms  that  seemed  to  be  normal  are  indicated 
by  the  drawings  in  figure  1  (page  122). 

Usually  no  attempt  was  made  to  represent  the  structure  of  the  cell 
content,  because  it  was  not  considered  of  taxonomic  vake.  In  those 
few  cases  in  which  the  structure  of  the  plasma  seemed  to  be  characteristic 
it  is  shown  in  a  very  approximate  way. 

The  microscopical  character  of  the  mycelium,  so  far  as  observed  by 
the  writer,  cannot  be  used  for  specific  differentiation  of  these  fungi ;  there- 
fore no  attention  has  been  given  it,  either  in  drawings  or  in  measurements, 
except  in  a  very  few  instances  when  certain  striking  peculiarities  have  been 
so  recorded  (Figs.  34m  and  43l). 

In  giving  measurements  of  the  size  of  spores,  it  was  considered  neces- 
sary, first,  to  give  an  average  size  for  conidia  from  a  particular  culture, 
as  well  as  the  average  of  the  measurements  for  the  entire  series  of  cultures. 
Thus  the  measurements  have  a  definite  meaning  and  are  comparal)le 
with  one  another,  provided  the  measurements  are  taken  separately  for 
each  type  of  spore. 

In  arranging  the  species  according  to  their  relationship  it  was  found 
convenient  to  follow  Wollenweber's  example  (1913  a: 26-27),  and  divide 
all  the  Fusaria  into  sections.  Most  of  the  sections  are  the  same  as  those 
of  Wollenweber,  but  because  of  some  organisms  presented  here  that  could 
not  be  placed  in  any  of  his  sections,  certain  new  sections  have  been  estab- 
lished provisionally. 

In  connection  with  taxonomic  study  and  presentation  of  the  Fusaria, 
it  is  necessary  to  discuss,  at  least  l^riefly,  the  conception  of  the  so-called 
normal  culture.  The  observations  of  the  writer  in  this  regard  are  princi- 
pally of  the  same  nature  as  those  of  Appel  and  Wollenweber  (1910:21-22) 
and  can  be  summarized  as  follows: 

1.  A  culture  can  be  in  the  state  of  undevelopment  {Ankullur)  when 
the  growth  shows  mycelium  to  the  entire  exclusion  of,  or  to  an  abnormally 

^  It  is  firmly  believed  that  standardization  of  the  subject  presented  is  especially  important  in  the  study 
of  this  difficult  group  of  fungi. 


FusARiA  OF  Potatoes  119 

poor  production  of,  spores;  other  forms  normally  present  in  the  culture 
may  also  be  absent.  This  state  of  culture  may  sometimes  exist  when  a 
fungus  is  transferred  from  a  mycelial  growth,  especially  when  it  is  taken 
directly  from  host  tissues. 

2.  A  culture  is  considered  to  be  a  normal  one  (Normkultur)  when  all 
forms  typical  to  the  fungus  —  and  especially  the  most  important  form, 
the  macroconidia  —  are  abundant,  comparatively  uniform  in  size  and 
shape,  smooth  in  outline,  and  so  forth. 

3.  After  a  long  cultivation  on  artificial  media,  a  fungus  may  lose  certain 
characters,  such  as  abihty  to  produce  certain  color  and  also  its  virulence 
as  a  parasite.  Such  a  state  of  culture  is  that  of  degeneration  (Abkultur), 
and  it  may  be  accompanied  also  by  smaller  size  and  abnormal  septation 
of  the  conidia.  (Only  loss  of  color  was  observed  by  the  writer;  the  other 
observations  are  those  of  Appel  and  Wollenweber,  1910:22.) 

4.  In  the  first  period  of  growth  of  any  one  of  the  Fusaria,  the  first 
conidia  produced  usually  soon  begin  to  produce  new  conidia,  sometimes  on 
minute  papillae  located  directly  on  the  conidial  walls,  and  sometimes  on 
more  or  less  well-differentiated  and  well-developed  conidiophores,  the  process 
often  much  resembling  the  budding  process  in  yeasts.  In  such  young 
cultures  the  conidia  are  more  or  less  swollen,  their  contents  are  com- 
monly densely  granular,  and  septation  is  not  clear.  This  period  (Jung- 
kultur)  may  last  from  one  to  five  or  more  days. 

5.  After  the  period  just  described,  the  fungus,  when  in  normal  con- 
dition, produces  conidia  which  remain  for  a  greater  or  a  less  length  of 
time,  of  perfectly  smooth  outhne  and  with  clear  septation.  At  this 
state  of  maturity  {Hochkultur)  the  conidia  are  also  of  most  uniform  and 
typical  shape  and  size,  and  it  is  the  important  stage  for  taxonomic  study 
of  these  organisms. 

6.  Finally  there  comes  a  period  (Altkultur)  in  which  the  conidia  begin 
to  disintegrate  through  the  process  of  self-digestion,  or  at  least  become 
of  less  uniform  and  perfect  type,  and  after  a  period  of  time  the  culture 
begins  to  lose  its  vitality. 

These  variations  in  character  of  the  cultures  show  that  only  normal 
and  mature  cultures  must  be  considered,  though  the  character  of  other 
conditions  may  also  give  some  help  in  identification.  Another  point  which 
must  be  clear  from  the  account  given  above  is  that  in  the  study  of  these 
fungi  they  must  be  grown  for  a  long  period  of  time,  under  different  cultural 
conditions  and  from  different  kinds  of  material  for  inocula.     Then,  after 


120  C.  D.  Sherbakoff 

observation  of  all  the  stages,  it  will  be  possible  to  pick  out  easily  the 
typical  and  normal  one  and  base  judgment  mainly  on  that.  Most  minute 
attention  must  be  paid  to  the  shape  of  macroconidia. 

In  order  to  avoid  much  of  the  possible  confusion  in  regard  to  the  color 
production  by  the  fungi,  it  will  perhaps  be  not  out  of  place  to  mention 
again  that  a  convenient  standard  of  colors  must  be  used.  Ridgway's 
(1912)  color  standards  have  been  used  in  this  work. 

IDENTIFICATION    OF   THE    FUSARIA   WITH    PREVIOUSLY   DESCRIBED 
SPECIES 

An  identification  of  the  Fusaria  of  potatoes  with  Fusaria  formerly 
described  as  occurring  on  other  substrata  and  even  on  potatoes,  is  in 
most  cases  impossible  or  at  least  rather  doubtful.  The  species  have  been 
described  mostly  from  material  as  it  was  collected  in  nature.  After 
what  has  been  said  in  the  foregoing  pages  about  variability  of  the  Fusaria, 
about  their  common  occurrence  in  different,  often  abnormal,  stages, 
about  the  necessity  of  most  'minute  attention  to  the  peculiarity  of  the 
shape  of  the  macroconidia,  and  about  the  importance  of  good  drawings 
and  of  measurements  properly  made  and  presented,  it  can  easily  be  seen 
what  small  chance  there  is  of  identifying  an  organism  from  any  typical 
description  of  one  of  these  species.  The  figures  are  often  absent,  and 
when  present  they  are  either  too  schematic  or  so  inaccurate  that  they 
might  just  as  well  be  omitted.  Any  citation  in  support  of  this  statement 
would  be  superfluous.^^ 

There  are  a  number  of  different  Fusaria  which  agree  with  a  certain 
description  and  therefore  might  be  considered  as  the  same  species.  At  the 
same  time  the  very  same  organism  may  have  other  characters  which, 
if  studied  alone,  would  surely  set  it  off  as  a  distinct  species.  An  extensive 
illustration  of  this  state  of  affairs  is  given  by  Appel  and  Wollenweber 
(1910:9-12),  but  the  most  impressive  case  is  that  of  Smith  and  Swingle 
(1904:50-51).  Therefore,  although  the  literature  on  the  subject  was 
fully  examined,  especially  publications  of  descriptions  supplemented  by 
any  kind  of  illustrations,  usually  no  definite  conclusion  in  regard  to  identity 
could  be  arrived  at.  Because  of  this,  and  also  because  the  most  important 
literature  is  already  hsted  in  a  few  works  on  this  subject  (especially  by 

35  Appel  and  Wollenweber  (1910 :  12)  in  this  connection  made  the  following  statement;  "  Oft  blieb  un3 
daher  waiter  nichts  ubrig,  als  neue  Naraen  zu  geben  und  ihnen  so  genaue  Beschreibungen  beizufiigen, 
dasa  nunmehr  die  Arten  immer  wieder  erkannt  werden  konnen." 


FusARiA  OF  Potatoes  121 

Appel  and  Wollenweber  in  1910,  and  by  Wollenweber  in  1913),  this 
literature  is  usually  not  cited  and  a  bibliography  is  omitted. 

The  condition  of  the  taxonomic  literature  on  species  of  the  genus 
Fusarium  in  general  is  characterized  by  Wollenweber  (1913  a:41)  as 
presenting  "  an  almost  hopeless  confusion."  The  only  favorable  exceptions 
known  to  the  writer  are  the  works  of  Wollenweber,  alone  and  in  associa- 
tion with  other  authors.  These  works  are  fully  considered  here.  In 
fact  there  is  hardly  any  difficulty  in  recognizing  Fusaria  described  by 
Wollenweber.  Nevertheless  all  available  cultures  of  his  organisms  were 
grown  along  with  the  other  Fusaria,  and  a  thorough  comparison  of  living 
material  was  made  whenever  it  was  necessary. 

When  this  work  was  actually  completed  there  appeared  the  work  of 
Lewis  (1913)  on  certain  disease-producing  species  of  Fusarium.  The  work 
was  supplemented  also  with  Wollenweber's  list  of  the  names  for  the  fungi 
studied  by  Lewis,  and  also  with  certain  remarks  by  Wollenweber  in  regard 
to  the  taxonomy  of  those  organisms.  It  appeared  that  certain  of  Lewis's 
organisms  were  the  same  as  those  isolated  by  the  writer  from  potatoes. 
Cultures  of  four  Fusaria,  somewhat  resembling  certain  species  isolated 
from  potatoes,  were  obtained  by  the  writer  through  the  courtesy  of  Dr. 
Morse,  Plant  Pathologist  in  the  Maine  Agricultural  Experiment  Station. 
On  comparison  these  four  organisms  —  F.  pirinum  (Fries)  Sacc,  F. 
conglutinans  Wr.,  F.  citrinum  n.  sp.,  and  F.  argillaceum  (Fries)  Sacc. — 
were  found  to  be  distinct  from  all  Fusaria  presented  here. 

SYSTEMATIC  ARRANGEMENT  OF  THE    SPECIES  OF  FUSARIUM    OF   POTATOES 

The  natural  key  to  the  species  and  their  arrangement  in  sections,^®  as 
given  here,  are  in  the  main  similar  to  those  of  Appel  and  Wollenweber 
(1910:59-60)  and  of  Wollenweber  (1913  a: 28-32),  respectively.  Some 
changes  and  additions  have  been  made,  however,  in  order  to  include 
many  new  organisms. 

Variety  is  used  as  the  smallest  unit  in  the  taxonomic  treatment  of  these 
fungi.  An  organism  is  classed  as  a  variety  if  it  differs  from  the  closely 
related  species  in  only  one  character,  even  though  the  difference  be  con- 
spicuous; the  same  treatment  holds  with  respect  to  the  organisms  that 
differ  slightly  in  a  few  characters.  When  the  differences  are  slight,  but 
in  several  important  characters,  the  organisms  are  classed  as  distinct 

36  The  term  is  used  by  Wollenweber  (1913  a:  28). 


122 


C.  D.  Sherbakoff 


species.     In  general  it  was  preferred  rather  to  name  a  possibly  good  species 
as  a  variety  than  to  raise  a  mere  variety  to  specific  rank. 


Fig.  1. —  Types  of  conidia  of  the  species  of  Fusarium  and  Fusarium-like  fxmgi  found  on 
potatoes.  A,  Ramularia  Solani;  b,  R.  eudidijma;  c,  R.  Magnusiana;  d,  Fusariuyn  affine;  e,  F. 
dimerum;  f,  F.  cuneiforme;  g,  F.  uduni  var  Solani;  h,  i,  j,  F.  ferruginosum;  k,  F.  sanguineum 
var.  pallidium;  l,  m,  n,  o,  p,  F.  arthrosporioides;  q,  F.  sporotrichioides;  r,  s,  F.  arthrosporioides 
var.  asporotrichius;  t,  F.  anguioides:  u,  F.  biforme;  v,  F.  lucidum;  w,  F.  subulatum;  x,  F.  fal- 
calum;  y,  F.  gibbosum;  z,  F.  caudatum  var.  Solani;  Ai,  F.  bullatum;  Bi,  F.  arcuosporum;  Ci, 
Di,  Ei,  F.  truncatum;  Fi,  F.  lululatum;  Gi,  Hi,  F.  anguslum;  u,  Ji,  Ki,  F.  orthoceras;  u,  F.  oxysporum 
var.  resupinalum;  Mi,  F.  oxysporum  var.  longius;  Ni,  F.  oxysporum;  Oi,  F.  sclerotioides;  Pi, 
F.  redolens  var.  Solani;  Qi,  F.  discolor;  Ri,  F.  clavatum;  Si,  Ti,  F.  subpallidum  var.  roseum;  Ui, 
Vi,  F.  trichothecioides;  Wi,  F.  discolor  var.  triseptatum:  Xi,  Ti,  F.  Solani:  Zi,  As,  F.  Martii;  B2, 
F.  coeruleum;  Ca,  F.  striatum;  D2,  F.  culmorum  var.  leleiiis.     Magnification  1000  times 


FusARiA  OF  Potatoes  123 

DICHOTOMOUS     KEY    TO    THE    SPECIES    OF    FUSARIUM   AND    FUSARIUM-LIKE 
FUNGI  OF    POTATOES 

Page 

a.  Conidia  "  not  typically  dorsiventral,  apex  rounded,  apedicellate RamulariA  264 

b.  Conidia  typically  one-septate 

c.  Average    diameter   of    one-septate    conidia    4.9  M R.  eudidyma  264 

ec.  Average  diameter  of  one-septate  conidia  3.9  M R.  Magnrisiana  265 

bb.  Conidia  typically  two-septate R.  Solani  267 

aa.  Conidia   typically   dorsiventral,    ape.x   more   or   less   attenuate,    mostly   pedicellate 

FUSARIUM    125 
b.  Conidia  typically  one-septate,  three  or  more  septa  never  present.  .Section  Dimerum   125 

c.  Ventrally  straight F.  affine  126 

cc.  Ventrally  curved F.  dimerum   127 

bb.  Conidia  typically  three^  or  more  septate 

c.  Dorsiventrality  slight Section  Ventricosum  128 

d.  Chlamydospores  terminal  only F.  cuneiforme   129 

dd.  Chlamydospores  terminal  and  intercalary F.  ventricosum   128 

cc.  Dorsiventrality  distinct 

d.  Conidia  apedicellate,  true  pionnotes  present.  .  .Section   Eupionnotes.    F.  udum  131 
dd.  Conidia  pedicellate,  true  pionuotes  absent 

e.  Conidia  with  gradually  attenuated,  pointed  ape.x 

f.  Conidia  prominently  broader  in  the  middle,   apex  long  and  narrow,  most 

prominently  pedicellate Section  Gibbosum  133 

g.  Dorsally  more  or  less  hyperbolic F.  gibbosum  133 

gg.  Dorsally  more  or  less  elliptic 

h.  Aerial  mycelium  poorly  developed,  fruiting  layers  in  form  of  a  pseu- 

dopionnotes F  falcatum  135 

hh.  Aerial  mycelium  well  developed 

i.  Conidia  typically  five-septate F.  falcatum  i-^ar. /liscwm  138 

ii.  Conidia  typically  five-  to  seven-septate F.  cavdatum  var.  Solani  140 

ff.  Conidia  of  about  equal  diameter  for  a  more  or  less  considerable  part  of 
their  length,  apex  not  very  lon^ 
g.  Conidia  typically  five-septate;  typical  color  of  conidial  masses  red,  of 
substratum  pink    to   orange    and    brown-red;    no    terminal   chlamy- 
dospores 
h.  Chlamydospores  absent 

i.  Microconidia  typically  absent Section  Roseum  142 

j.  Blue  sclerotia  present F.  acuminatum  142 

jj.  Blue  sclerotia  absent 

k.  Conidia  tj'pically  in  pseudopionnotes;  aerial  mycelium  weakly 

developed  or  absent F.  mctacroum  143 

kk.  Conidia  typically  in  distinct    sporodochia;    aerial    mycelium 
well  developed 
1.  Sporodochia  small,  bocne  on  aerial  mycelium  and  without 

plectenchymic  base F.  subulatum  147 

11.  Sporodochia  large,  with  plectenchymic  base 

m.  Six -septate  conidia  typically  present F.  effusum   151 

mm.  Six-septate  conidia  typically  absent 

n.  Five-septate  conidia  dominant  type F.  lucidum  157 

rm.  Three-  and  five-septate  conidia  about  equally  present, 

or  three-septate  dominant F.  truncatum  155 

3'  The  term  conidia  is  used  here,  in  this  key  and  elsewhere,  ia  the  sense  of  macrocooidia. 


124  C.  D.  Sherbakoff 

Page 

ii.  Microconidia   typically    present,  usually  spindle-shaped,     non-  to 

three-septate Section  Arthrosporiella  161 

j.  SLx-  to  seven-septate  conidia  typically  present,  at  least  in  pseudo- 
pionnotal  stage 
k.  Distinct  sporodochia  present 

1.  Substratum  and  aerial  mycelium  near  it  typically  of  carmine 

hues,  causal  layer  of  aerial  mycelium  pink F.  biforme  166 

11.  Substratum  of  a  clay  color,  aerial  mycelium  white 

F.  diversisporum  161 
kk.  No   conspicuous  sporodochia,  fruiting  layer  on  moist  media 

commonly  in  form  of  a  pseudopionnotes F.  anguioides  169 

jj.  Six-  to  seven-septate  conidia  absent F.  arthrosporioides  175 

hh.  Chlamydospores  present,  typically  intercalary  only 

i.  Microconidia  present,  pyriform Section  Sporotrichiella  183 

F.  sporotrichioides  183 

ii.  Microconidia  absent  or  not  pyriform Section  Ferruginosum  186 

j.  Typical  macroconidia  of  about  equal  diameter  for  a  considerable 
length,  or  not  prominentlj'  broader  in  the  middle,  in  some  cases 
approaching  the  subulatum  type,  much  curved 
k.  Chlamydospores  typically  only  in  mycelium 

1.  Chlamydospores  sparse,  never  in  masses  nor  in  long  chains.  . 

F.  arcuosporum  186 
11.  Chlamydospores  typically  abundant,  commonly  in  masses  of 

long  chains  and  in  clusters F .  ferrugiyiosum  190 

kk.  Chlamydospores  also    in   conidia  or  in  conidia  only 

F.  sanguineum  193 
jj.  Macroconidia  typically  noticeably  broader  at  the   middle,   not 

very  pointed  at  the  apex,  not  much  curved F.  hullalum  198 

gg.  Conidia  typically  three-septate;   typical  color  of  substratum  vinaceous 
red  to  purplish  vinaceous;   terminal  and  intercalary  chlamydospores 

present Section  Elegans  202 

h.  Conidiophores  simple  or  only  slightly  branched 

i.  Average  macroconidia  36  M  long F.  orthoceras  202 

ii.  Average  macroconidia  45.6  M  long F.  angustum  203 

hh.  Conidiophores  typically  much  branched 

i.  In  plate  cultures   on  neutral  potato   agar   producing   exposed  and 
distinct  pseudopionnotes 
j.  Color  of  the  pseudopionnotes  vinaceous  red.F.  redolens  var.  Solani  205 

jj.  Color  of  the  pseudopionnotes  vinaceous  purple F.  lutulatum  209 

ii.  No   exposed    and    distinct  pseudopionnotes  in  potato  agar  plate 
cultures 

j.  Macroconidia  typically  somewhat  broader  toward  apex 

F.  scleroiioides  214 
jj.  Macroconidia  typically  not  broader  toward  apex.  .  .F.  oxysporum  220 
ee.  Conidia  with  more  or  less  abruptly  attenuated  apex,  rounded  or  papillate 
f.  Substratum  typically  (on  glucose  agar)  carmine  red.     The  color  may  be 

yellowish,  but  never  gray,  green,  nor  blue Section  Discolor  228 

g.  Conidia  non-  to  three-septate,  rounded  at  both  ends,  of  common  type, 

numerous  (those  of  discolor  tj'pe  usually  only  few) .  .F.  trichothecioides  229 
gg.  Discolor  type  of  conidia  common,  and  nearly  the  only  type  present 
h.  Conidial  masses  pale  cream  to  pale  pink  in  color,  aerial  mycelium  well 

developed  and  nearly  white F.  subpallidum  230 


FusARiA  OF  Potatoes  125 

Page 
hh.  Conidial  masses  of  pale  orange  to  dark  chocolate-red  in  color,  my- 
celium from  nearly  slightly  pinkish  to  dense  carmine  red 

i.  Conidia  much  broadened  toward  apex F.  clavatum  234 

ii.  Conidia  not  or  only  slightly  broadened  toward  apex 

j.  Average  diameter  of  five-septate  conidia  from  4  to  4.4  M 

F.  discolor  236 

jj.  Average  diameter  of  five-septate  conidia  from  5.8  to  G.8  M 

F.  culmorum  240 
ff.  Substratum  typically  (on  a  neutral    or    not  strongly  acid  glucose  agar) 
brownish    gray,  vinaceous  red,  vinaceom  purple,  or  blue,  but    never 

carmine  red Section  Martial  a  244 

g.  Macroconidia  of  even  diameter  or  slightly  broader  toward  apex 

h.  Macroconidia  comparatively  long  and  narrow  (from  7.4  to  9.3  times 
longer  than  broad) 

i.  Average  three-septate  conidia  from  37  to  49  M  long F.  Martii  244 

ii.  Average  three-septate  conidia  from  34  to  35  M  long 

j.  Pseudopionnotes  on  an  agar  typically  present,  aerial  mycelium 

poorly   developed: F.  striatum  255 

jj.  Pseudopionnotes  on  an  agar  typically  absent,  aerial  mycelium 

well  developed F.  radicicola  257 

hh.  Macroconidia  comparatively  short  and  broad  (only  about  5.5  times 

longer  than  broad) F.  Solani  251 

gg.  Macroconidia  typically  somewhat  broader  tov/ard  basal  end 

F.  coeruleum  260 

DESCRIPTIONS  OF  SECTIONS,   GENERA,   SPECIES,   AND  VARIETIES 

FUSARIUM  Link 

Link,  Mag.  Ges.  nat.  Freunde  3:10.  1824.  Saccardo,  Syll.  Fung. 
4:694.  1886.  (Cf.  Appel.  0.,  and  Wollenwel^er,  H.  W.,  Arb.  K.  biol.  Anst. 
Land-  u.  Forstw.  8.: 60-61.  1910.  Wollenweber,  H.  W.,  Phytopath. 
3:24-50,  197-240,  fig.  1,  Pis.  i  and  iii.  1913;  Ber.  deut.  Bot.  Gesell.  31 :17- 
34.     1913.     Journ.  Agr.  Research  2 :  251-285.     1914.) 

Hyphomycetes,  with  from  hyaline  to  bright,  but  never  plain  gray  nor 
black,  conidia  and  mycelium;  conidia  sickle-shaped,  septate  (usually 
3-  or  mo.'e  septate),  apically  pointed,  mostly  pedicellate,  not  appendic- 
ulate,  noncatenulate;  conidia  scattered  over  substratum,  in  pseudo- 
pionnotes or  in  sporodochia,  the  latter  without  or  with  from  flat  to  wart- 
like plectenchymic  substratum,  and  always  without  any  differentiated 
enclosing  or  surrounding  structures;  conidiophores  from  simple  to  irregu- 
larly verticillate. 

L   Section    Dimerum     n.  sec. 

Conidia  dorsiventral,  1-septate;  chlamydospores  may  be  present. 
•    This  section  is  proposed  in  order  that  Fusaria  with  1-septate  conidia 
may  be  included.     The  two  species  of  this  section  are  comparatively 


126 


C.  D.  Sherbakoff 


slow-growing  fungi,  with  hyaline  or  nearly  hyaline  mycelium  and  from 
hyaline  to  orange-colored  conidia.  They  appear  to  differ  in  many  ways 
from  typical  Fusaria,  but  the  differences  are  not  sharp  enough  to  warrant 
transferring  them  into  another  genus. 


Rev. 


1.  Fusarium  affine  Faut.  et  Lamb.   (Figs.  Id  and  2) 
Fautrey,  F.,  and  Lambotte,  E.,  Especes  nouvelles  ou  rares  de  la  Cote-d'Or, 
Myc.  Fr.  i8:68.  1896.     Saccardo,  Syll.  Fung.  14: 1125.     1899. 

Conidia  straight,  somewhat  dorsiventral  near  apex,  apedi- 
cellate,  typically  1-septate,  10.2  x  2.8  (9-11.4  x  2.6-3)  m, 
usually  in  a  continuous  smooth  or  slightly  roughened, 
slimy  layer,  from  hyaline  to  pale  salmon-colored  on  a 
glucose  agar;  conidiophores  from  simple  to  sparingly 
branched,  septate;  mycelium  hyaline;  no  chlamy  do- 
spores. 

Hab.  In  tubers  and  stems  of  Solarium  hiberosum,  in 
greenhouse  soil,  New  York. 

This  organism  was  repeatedly  isolated  from  various 
sources  such  as  discolored  fibrovascular  bundles  of  potato 
tubers,  from  the  base  of  wilted  potato  stems,  and  from 
soil.  Its  size  is  exactly  the  same  as  that  given  by  Wol- 
lenweber  (1913  c:229)  for  the  conidial  stage  of  Myco- 
Wr.     Wollenweber's  illustra- 


FiG.  2.—  Fusa- 
rium affine.  a, 
Conidia     from 

35-days-old  cul-  ,    t.  \ 

ture  on  slightly  sphaerella  bolani  (E.  et  E.) 


acidified  potato  tions  (Plate  XXI,  fig.  n)  are  also  much  the  same,  and  he 

agar;  B,  conidia  •  ■,         n        rr        V^                  t        1                             •  t   1 

from  7-days-old  considers  t .  affine  }}  aut.  et  Lamb,  as  the  conidial  stage. 

■plate  culture  on  'jj^g  strain  studied  did  not  show  any  perfect  form  in  cul- 

hard     potato  iii. 

agar;  c,  conidia  ture,  although  it  was  grown  for  more  than  a  year  and  on 

from    U-days-  yarious  media.     This  organism  can  be  at  once  distinguished 

old   culture    on  _,          .        ,         .             .  ' 

red     raspberry  irom   all  the    other    l^  usaria    by    its    minute,    1-septate, 

cane   plug;  d,  nearly  straight  conidia  and  its  inconspicuous,  slow  growth. 

days-old  culture  For  a  fuller  presentation  of  its  septation  and  size  the 

on  hard  lima-  following  detailed  measurements  are  given: 

bean   agar;    e, 

conidiophores  Qj^  pg^j  raspberry  cane  plug,  culture  seventy-four  days 

from     various  t-          ^                 r-     &>                                    j                   j 

media;    f,     co-  old: 

riidia  from  5-  Conidia:     0-septate,  45  per  cent,  7  x  2.2  (3.5-9  x  1. 7-2.6) /z 

days-old  culture  ^ 

on  nutrient  agar  1-septate,  55  per  cent,  9  X  2.6  (6-12  X  2-3)  M 


FusARiA  OF  Potatoes 

On  hard   lima-bean   agar,    culture   four   days  old: 
Conidia:     0-septate,  40  per  cent 

1-septate,  60  per  cent,  10.2  x  3  (9-11  x  2.8-3.8) /x 

On  nutrient   agar,    culture   six   days   old: 
Conidia:     0-septate,  10  per  cent 

1-septate,  90  per  cent,  11.4  x  2.8  (8.7- 
13  x  2.4-3.5)m 

Average  of  the  above  measurements: 
Conidia:     0-septate,  32  per  cent,  7  x  2.2^1 

1-septate,  68  per  cent,  10.2  x  2.8ai 

The  size  of  the  spores  of  F.  affi,ne  as  given  by 
Saccardo  (10-15  x  4^)  differs  somewhat  from  the 
above,  but  the  description  otherwise  is  so  much  the 
same  that  the  organisms  can  be  considered  iden- 
tical. 


127 


2.  Fusarium  dimerum  Penz.  (Figs.  1e  and  3) 

Penzig,  O.,  Micheha  2:484.  1882.  Saccardo, 
Syll.  Fung.  4:704.  1886.  Lindau,  Rab.  Krypt. 
Fl.  Pilze  9:566.  1910.  Appel  and  Wollenweber, 
Arb.  K.  biol.  Anst.  Land-  u.  Forstw.  8:37,  text 
figs.  2  and  4.     1910. 

Conidia  lunar,  somewhat  pedicellate,  typically 
1-septate,  13  x  3.3  (12.5-13.5  x  3.3-3.4)/i,  often 
also  0-septate,  rarely  2-  or  3-septate,  borne  singly 
on  the  mycelium  or  forming  a  more  or  less  contin- 
uous slimy  layer,  from  hyaline  to  cinnamon-buff 
on  glucose  agar;  mycelium  from  hyaline  to  about 
the  color  of  the  conidial  masses;  chlamydospores 
intercalary,  in  mycelium. 

Hab.  On  tubers  and  stems  of  Solanum  tuberosum  in  Germany  and  in 
Minnesota  (U.  S.  A.),  and  on  fruits  of  Citrus  medica  in  Italy. 

The  fungus  is  easily  distinguished  from  all  the  other  Fusaria  by  its  lunar, 
minute,  1-septate  conidia.  It  was  isolated  by  the  author  only  once, 
from  a  superficial  dry  rot  of  potato  tuber  received  from  St.  Paul,  Minnesota. 


Fig.  3. —  Fuaarium  di- 
merum. A,  Pseudopion- 
notal  conidia  from  70- 
days-old  culture;  b, 
conidiophore,  c,  pseu- 
dopionnotnl  conidia, 
from  19-days-oId  cul- 
ture on  slightly  acidified 
hard  potato  agar;  d, 
conidiophore  from  70- 
days-old  culture  on  po- 
tato stem  plug;  e,  co- 
nidia, F,  conidiophore, 
from  43-days-old  ctdture 
on  hard  lima-bean  agar 
with  2  per  cent  glucose; 
G,  chlamydospores;  h, 
conidiophores,  i,  co- 
nidia, from  21 -days-old 
culture  on  hard  lima- 
bean  agar 


128  CD.  Sherbakoff 

The  measurements  of  the  conidia  in  detail  are  as  follows : 

On  hard  potato  agar,  slightly  acidified,  culture  eighteen  days  old: 
Conidia:    0-septate,  3  per  cent 

1-septate,  97  per  cent,  12.5  x  3.4  (10-18  x  2.9-4.1)^ 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  forty-three  days 
old: 
Conidia:     0-septate,  12  per  cent,  10  x  3.8yu 

1-septate,  88  per  cent,  12  x  3.3  (10-18  x  3-3.5)^ 

On  hard  lima-bean  agar,  culture  twenty-one  days  old : 
Conidia:     0-septate,  27  per  cent,  11.5  x  3.2  (9-14  x  2.9-3.5)m 
1-septate,  73  per  cent,  12.5  x  3.3  (10-17  x  2.9-3.9)ju 

Average  of  the  above  measurements: 
Conidia:     0-septate,  14  per  cent,  10.8  x  3.5/i 
1-septate,  86  per  cent,  12.8  x  3.3m 

The  organism  studied  is  so  much  the  same  as  F.  dimerum  originally  de- 
scribed by  Penzig,  that  it  is  considered  identical.  A  similar  organism  is 
also  reported  as  occurring  on  potato  in  Germany  (Appel  and  Wollen- 
weber,  1910:37).  The  only  peculiarity  of  the  organism  which  either  was 
not  observed  or  was  not  present  at  all  in  the  original  F.  dimerum  is  that  the 
septum  in  the  conidia  of  the  organism  studied  is  often  and  conspicuously 
acentric. 

II.  Section  Ventricosum  Wr.,  Phytopath.  3:32 

Conidia  only  slightly  dorsi ventral,  somewhat  wedge-shaped,  broader 
toward  base,  apex  somewhat  rounded,  apedicellate,  typically  3-septate; 
no  sporodochia;  chlamydospores  variable,^^  always  present. 

3.  Fusarium  ventricosum.  Ap.  et  Wr, 

WoUenweber,  H.  W.,  Phytopath.  3:32,  fig.  1,  a  and  v.     1913. 

Wollenweber  describes  this  species  as  follows:  "Conidia  never  formed 
in  sporodochia,  brownish-white  to  cream-colored,  3-septate,  29-37  x  5.75- 
7.5m;  conidiophores  bostryx-like  or  irregularly  branched,  chlamydospores 

like  those  of  the  section  Elegans.     Wound  parasite, found  in 

Europe.     Inhabits  also  Beta  vidgaris." 

The  organism  was  neither  isolated  nor  studied  by  the  writer. 

^'According  to  Wollenwelier  the  chlamydospores  are  of  Elegans  type,  that  is,  terminal  and  intercalary, 
0-  to  1-  or  more  septate.  In  order  to  include  F.  cuneiforme  it  was  necessary  to  alter  the  characterization 
of  the  chlamydospores  in  this  section. 


FusARiA  OF  Potatoes 


129 


4.  Fusarium  cimeiforme  n.  sp.  (Figs.  1  f  and  4) 

Conidia  only  slightly  dorsiventral,  more  or  less  wedge-shaped,  broader 
toward  the  base,  with  apex  somewhat  rounded,  apedicellate,  typically 
3-septate,  34.7x5.6  (30-41  x  5.6-6) /x,  often  0-  to  2-septate,  in  false 
balls,  from  hjailine  to  cream-colored;  no  sporodochja;  aerial  mycelium 
hyaline,  in  a  high  tuft  in  center,  and  short,  distinctly  zonate,  outside; 
chlamydospores  from  smooth  to  very  distinctly  warted,  sometimes  suiv 
rounded  with  a  gelatinous  capsule,  terminal  only,  typically  unicellular, 
8.2  X  7.6  (7.6-8.5  x  7.3-8.1)/x. 


Fig.  4. —  Fusarium  cuneiforme.  a,  Conidia  from  false  balls  of  16-days-old  culture  on  slightly 
acidified  hard  -potato  agar;  b,  conidia  from  false  balls  from  10-day s-old  -potato  agar  with  0.5 
per  cent  glucose;  c,  conidiophores,  d,  conidia,  fro?n  a  thin  layer  of  73-days-old  culture  on  red 
raspberry  cane  plug;  e,  conidia  from  confluent  thin  mass  of  false  balls  of  6^-days-old  culture 
on  hard  bean  agar;  f,  terminal  chlarnydospores,  G,  conidiophore,  from  3/i.-days-old  culture  on 
hard  lima-bean  agar;  h,  terminal  chlamydospores  of  16-days-old  culture  on  slightly  acidified 
hard  potato  agar;  i,  conidia,  j,  tips  of  conidiophores  showing  beginning  of  production  of  new 
conidia,  from  34-days-old  culture  on  hard  lima-bean  agar;  k,  conidia,  h,  t^r7ninal  chlamydospores, 
from  26-days-old  corn  agar;  m,  anastomosis,  and  chlamydospore  producing  conidia  from  34- 
days-old  culture  on  hard  lima-bean  agar;  n,  terminal  chlamydospores  from  the  same  culture 


Hab.  The  fungus  was  isolated  from  soft  rotted  potato  tubers  received 
from  Auburn,  Alabama,  and  from  Atlanta,  New  York,  always  in  association 
with  bacteria  and  other  fungi. 

Differs  from  F.  ventricosum  Ap.  et  Wr.  mainly  in  typically  0-septate 
chlamydospores  which  are  terminal  only.  There  seems  to  be  some  differ- 
ence also  in  the  shape  and  size  of  the  conidia,  which  here  are  somewhat 
more  slender. 


130  C.  D.  Sherbakoff 

Latin  description. — Conidiis  parum  dorsiventralibus,  plus  minusve  cunei- 
formibus,  deorsum  latioribus,  apice  subrotundato,  apedicellatis,  typice 
3-septatis,  34.7  x  5.6  (30-41  x  5.6-6)/x,  0-2-septatis,  globis  falsis,  ex  hyalino 
"cream  color"  (R);  nullis  sporodochiis;  aerio  mycelio  hyalino,  medio  alte 
cristato,  extra  brevi  et  distincte  zonato;  chlamydosporis  levibus  vel 
maxime  distincte  verrucosis,  interdum  capsula  gelatinosa  cinctis,  tantum 
terminalibus,  typice  unicellularibus,  8.2  x  7.6  (7.6-8.5  x  7.3-8. l)/x. 

Hab.  Fungus  ex  tuberibus  mollibus  putridisque  Solani  tuberosi  ab 
Auburn,  Alabama,  et  Atlanta,  New  York,  Amer.  bor.  receptis,  semper 
una  cum  bacteriis  aliisque  fungis,  sejungebatur. 

The  measurements  of  conidia  on  different  media  are  as  follows: 
On  slightly  acidified  hard  potato  agar,  culture  sixteen  days  old: 
Conidia:*  0-septate,  rare,  16  x  4/i 
1-septate,  rare,  21  x  5.2/i 

2-septate,  1  per  cent,  24  x  5.6  (20-32  x  5.2-5.8) m 
3-septate,  99  per  cent,  35.5  x  6  (24-44  x  4.7-7.5)  m 

On  red  raspberry  cane  plug,  culture  seventy-three  days  old: 
Conidia:     0-septate,  12  per  cent,  14  x  5.9  (6.5-17  x  5-6.5)^1 
1-septate,  34  per  cent,  19  x  6  (15-27  x  4.8-7)  m 
2-septate,  11  per  cent,  33  x  5.9  (20-40  x  5.2-6.5) m 
3-septate,  43  per  cent,  33  x  5.9  (20-40  x  5.2-6.5)m 

On  hard  potato  agar,  culture  twenty-five  days  old : 
Conidia:     1-septate,  rare 

3-septate,  100  per  cent,  35  x  5.8  (24-48  x  5-6.5) /i 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  sixty-four  days 

old: 

Conidia:     0-septate,  4  per  cent 

1-septate,  64  per  cent,  25  x  4.9  (12-41  x  3.5-6.5)m 
2-septate,  22  per  cent,  28  x  5.5  (23-32  x  4.8-5.9) /x 
3-septate,  10  per  cent,  30  x  5.6  (24-38  x  4.8-6.2) m 

On  hard  lima-bean  agar,  culture  thirty-four  days  old,  advanced  part  of 
colony  growth: 
Conidia:     0-septate,  rare 

1-septate,  17  per  cent 

2-septate,  7  per  cent 

3-septate,  76  per  cent,  31.5  x  6  (27-41  x  5.2-7.6)m 


FusARiA  OF  Potatoes  131 

On  same  culture  as  above  but  from  an  old  part  of  the  colony  growth : 
3-septate,  70  per  cent,  41  x  6  (36^6  x  5.2-7.6) /x 

Average  of  the  above  measurements: 
Conidia:     0-septate,  3  per  cent,  15  x  5/i 

1-septate,  23  per  cent,  21.3  x  5Aix 
2-septate,  8  per  cent,  26  x  5.45/^ 
3-septate,  66  per  cent,  34.7  x  5.9fx 

III.  Section  Eupionnotes  Wr.,  Phytopath.  3:38,  206,  219 

Conidia  dorsiventral,  apedicellate,  nearly  cylindrical  for  the  largest 
part  or  slightly  broader  toward  apex,  typically  3-septate,  in  true  pionnotes ; 
terminal  and  intercalary  chlamydospores  present.  Differs  from  all  the 
other  sections  of  Fusaria  by  true  pionnotal  fruiting  form. 

5.  Fusariiim.  udum  (Berk.)  Wr. 

Syn.  Fusisporium  udum  Berk.,  Ann.  Mag.  Nat.  Hist.  6:438,  PI.  xiv,  fig.  28.     1841. 
Pionnotes  uda  (Berk.)  Sacc,  Syll.  Fung.  4:726.     1886. 

Cf.  Wollenweber,  Phytopath.  3:38  (footnote),  219  (key),  PI.  xxi,  figs. 
R  and  s. 

According  to  Wollenweber's  data  and  figures,  the  conidia  are  dorsiventral 
with  somewhat  rounded  apex,  apedicellate,  typically  3-septate,  about 
33-45  X  3.5-4)u,  sometimes  4-  or  5-septate;  terminal  chlamydospores 
present. 

Hab.  On  cut  surfaces  of  oak,  elm,  and  other  trees,  also  on  Solanum 
tuherosimi,  on  tulip  bulbs,  and  in  the  soil. 

6.  Fusarium  iidum  (Berk.)  Wr.  var.  Solani  n.  var.  (Figs.  1g  and  5) 
Conidia  dorsiventral,  usually  somewhat  broader  toward    the   slightly 

rounded  apex,  apedicellate,  typically  3-septate,  30.2  x  4.27  (25-34  x  4-4.5) m, 
non-  to  two-septate  very  rare  when  mature,  4-  and  5-septate  rare,  of  from 
light  vinaceous  cinnamon  to  orange-cinnamon  hues  on  agars  rich  in  glucose; 
chlamydospores  usually  found  only  in  old  cultures,  terminal  and  inter- 
calary, in  conidia,  in  the  tips  of  sterigmata,  and  in  mycelium,  often  of 
dense  orange  color,  0-septate,  6  x  5.5 ijl;  aerial  mycelium  present  only  near 
margin  of  colony  growth,  very  loose,  short,  hyahne;  substratum  colorless 
or  approaching  the  color  of  the  conidia. 


132 


C.  D.  Sherbakoff 


Hab.  On  rotted  tubers  of  Solanuni  tuberosum,  together  with  Ramularia 
Solani,  Long  Island,  New  York. 

Differs  from  F.  udum  (Berk.)  Wr.  in  that  the  conidia  are  shorter  and 
thicker,  and  somewhat  broader  toward  the  apex. 

The  following  measurements  were  taken: 

On  slightly  acidified  hard  potato  agar,  culture  eight  days  old: 
Conidia:     0-  and  1-septate,  only  when  young 

3-septate,  100  per  cent,  33  x  4.25  (28-39  x  3.5-4.7) m 


^iG.  5. —  Fusarium  udum  var.  Solani.  a,  Different  forms  of  chlamydospores  from  85-days- 
ol4  culture  on  hard  potato  agar  with  5  per  cent  glucose;  B,  conidia  from  9-days-old  culture  on 
har^  lima-bean  agar;  c,  conidia,  d,  conidiophores,  from  49-days-old  culture  on  rye  straw;  e, 
conidiophores  {magnijied  250  times)  from  8-days-old  culture  on  slightly  acidified  hard  potato 
agar;  f,  conidia  from  72-days-old  culture  on  potato  tuber  plug;  G,  conidia,  H,  conidiophores, 
from  8-days-old  cidture  on  slightly  acidified  hard  potato  agar;  i,  conidia,  j,  k,  conidiophores, 
fro?n  74-days-old  culture  on  red  raspberry  cane  plug 


On  red  raspberry  cane  plug,  culture  seventy-four  days  old: 

(1)  From  an  advanced  part  of  colony  growth 
Conidia:     1-septate,  rare 

2-septate,  10  per  cent,  22  x  3.8  (19.5-24  x  3.3^.1)/i 
3-septate,  90  per  cent,  25  x  4  (22-31  x  3.9-4.6) m 

(2)  From  an  old  part  of  colony  growth 

Conidia:     3-septate,  100  per  cent,  28  x  4/i  dominant  type 
4-septate,  rare 


FusARiA  OF  Potatoes  133 

On  potato  tuber  plug,  culture  seventy-two  days  old : 
Conidia:     0-septate,  rare,  young 

1-septate,  5  per  cent,  mostly  young 
2-septate,  2  per  cent,  mostly  young 
3-septate,  86  per  cent,  31  x  4.4  (23-40  x  3.9-4.7)^ 
4-septate,  7  per  cent,  32  x  4.4  (28-40  x  4. 1-4.7)  m 
5-septate,  rare,  35  x  4.4  (30^0  x  4-4.6) /x 

On  hard  lima-bean  agar,  culture  four  days  old: 
Conidia:     1-septate,  1  per  cent,  young 
2-septate,  4  per  cent,  31  x  4.4 
3-septate,  95  per  cent,  34  x  4.5  (25-40  x  4.1-4.9)/* 
4-septate,  rare,  40  x  5.1  (only  a  few  measured) 

Average  of  the  above  measurements: 
Conidia:     0-septate,  rare  to  none 

1-septate,  1.5  per  cent,  (usually  immature) 
2-septate,  4  per  cent 
3-septate,  93  per  cent,  30.2  x  4.27/* 
4-septate,  1.5  per  cent,  36  x  4.75/* 
5-septate,  rare  to  none 

IV.  Section  Gibbosum  Wr.,  Phytopath.  3:31,  fig.  1,  l  and  m 

Conidia  with  from  hyperbolic  or  parabolic  to  elliptic  dorsal  curve, 
conspicuously  broader  in  the  middle,  with  more  or  less  long,  narrow  apex, 
prominently  pedicellate,  mostly  5-septate;  intercalary  chlamydospores 
always  present;  color  of  substratum  and  conidial  mass  typically  from 
pale  buff  to  cinnamon  and  sepia;  mycelium  from  hyaline  to  brown. 

7.  Fusarium  gibbosum  Ap.  et  Wr.  (Figs.  1y  and  6) 

Appel,  O.,  and  Wollenweber,  H.  W.,  Arb.  K.  biol.  Anst.  Land-  u.  Forstw. 
8 :  185-190,  text  fig.  10,  c  and  d.  1910.  Wollenweber,  H.  W.,  Phytopath. 
3:32,  fig.  1,M.    1913. 

Conidia  often  with  hyperbolic  dorsal  curve,  conspicuously  broader  in 
the  middle,  with  long,  narrow  apex,  prominently  pedicellate,  typically 
5-septate,  41.6x4.6  (40-^6  x  4.4-4.7) /t, sometimes  also  0-  to  7-septate,  in 
minute  nonconverging  sporodochia  or  spreading  over  mycelium  singly, 
from  hyaline  to  light  pinkish  cinnamon  in  color;  chlamydospores  inter- 


134 


C.  D.  Sherbakoff 


calary,  always  present;  aerial  mycelium  typically  present,  short,  fine, 
medium  loose;  colony  faintly  zonate;  substratum  on  potato  agar  rich  in 
glucose,  from  pale  flesh  to  cinnamon  in  color. 

Hab.  On  stems  and  tubers  of  Solarium  tuberosum  in  Germany,  rare. 

The  organism  was  not  isolated  by  the  writer,  but  a  culture  of  it  was 
carefully  examined  on  several  different  media  with  the  following  results 
in  regard  to  spore  septation  and  size: 

On  slightly  acidified  hard  potato  agar,  culture  twenty-four  days  old : 
Conidia:     3-septate,  5  per  cent 

4-septate,  15  per  cent,  32-4.  lyu 

5-septate,  80  per  cent,  43.2  x  4.6(38-50  x  4.3-4.9)^ 


Fig.  G. —  Fusarium  gihbosum.  a,  Pseiidopionnotal  conidia  from  10-days-old  culture  on 
hard  lima-bean  agar;  b,  intercalary  chlamydospores,  c,  conidia,  from  71 -days-old  culture  on 
nd  raspberry  cane  plug;  d,  pseudopionnotal  conidia  from  118-days-old  culture  on  hard  lima- 
bean  agar  with  2  per  cent  glucose;  e,  conidia  from  42-days-old  culture  on  potato  stem  plug; 
F,  pseudopionnotal  conidia  from  24-days-old  culture  on  slightly  aridified  hard  potato  agar 


On  red  raspberry  cane  plug,  culture  seventy-one  days  old : 
Conidia:    3-septate,  5  per  cent 
4-septate,  5  per  cent 

5-septate,  90  per  cent,  40  x  4.6  (33-46  x  4.2-5.2) /: 
6-septate,  rare 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  one  hundred 
and  eighteen  days  old: 
Conidia:     4-septate,  1  per  cent 

5-septate,  94  per  cent,  37  x  4.6  (26-44  x  3.9-4.9)m 

6-septate,  3  per  cent,  42  x  4.7/x 

7-septate,  2  per  cent 


FusARiA  OF  Potatoes  135 

On  hard  lima-bean  agar,  culture  ten  days  old: 
Conidia:     0-septate,  1.5  per  cent,  7.5  x  3.2  ix 

1-septate,  4  per  cent,  10  x  3.2  (7-17  x  2.7-3.5)m 

2-septate,  very  rare 

3-septate,  4  per  cent,  27x4.1  (19-41  x  3.5-4.1)^ 

4-septate,  3  per  cent 

5-septate,  86  per  cent,  46  x  4.4  (35-58  x  4-4.8)  m 

6-septate,  1.5  per  cent,  52x4.5  (50-60  x  4.3-4.8)  m 

Average  of  the  above  measurements : 
Conidia:     0-septate,  0.5  per  cent,  7,5  x  3.2^i 
1-septate,  1  per  cent,  10  x  3.2/i 
2-septate,  very  rare 
3-septate,  4  per  cent,  27  x  4.1/* 
4-septate,  6  per  cent,  27  x  4.1/* 
5-septate,  87  per  cent,  41.6  x  4.6iU 
6-  and  7-septate,  1.5  per  cent,  47  x  4.6/x 

The  averages  of  Appel  and  Wollenweber's   (1910:189-190)   measure- 
ments are  as  follows: 
Conidia:     3-septate,  3  per  cent,  25  x  4.5/x 

4-septate,  2  per  cent,  29  x  4.5m 

5-septate,  59  per  cent,  42  x  4.4/* 

6-septate,  23  per  cent,  49  x  4.6^ 

7-septate,  13  per  cent,  49  x  4.7ai 

There  is  a  notable  difference  between  the  data  presented  by  the  writer 
and  those  of  Wollenweber  only  in  the  proportion  of  6-  and  7-septate 
conidia,  the  size  of  5-  and  of  6-  and  7-septate  conidia  being  very  much  the 
same. 

8.  Fusarium  jalcatum  Ap.  et  Wr.  (Figs.  Ix  and  7) 

Appel,  0.,  and  Wollenweber,  H.  W.,  Arb.  K.  biol.  Anst.  Land-  u. 
Forstw.  8:175-185;  PI.  ii,  figs.  100  to  110;  PI.  iii,  fig.  9;  text  fig.  10,  a. 
1910. 

Syn.  Fusarium  vasinfedum  var.  Pisi  Schikorra,  Arb.  K.  biol.  Anst.  Land-  u.  Forstw.  4: 157, 
PI.  VII,  1906;  notF.  vasinfectum  var.  Pisi  van  Hall,  Ber.  deut.  Bot.  Gesell.  21 : 4,  pi.  4, 1903. 
WoUenweber,  Phytopath.  3:31,  fig.  1,  l,  1913. 


136 


C.  D.  Sherbakoff 


Conidia  often  with  parabolic  dorsal  curve,  conspicuously  broader  in 
the  middle,  with  long  and  narrow  apex,  prominently  pedicellate,  typically 
5-septate,  49.1x4.6  (43-54.5  x  4.5-4,7) m,  often  3-  to  7-septate,  0-  to 
2-  and  8-septate  very  rare,  in  minute  sporodochia  more  or  less  converging 
into  pseudopionnotes,  from  buff-pink  to  cinnamon  on  hard  potato  agar 
rich  in  glucose;  intercalary  chlamydospores  always  present;  aerial  mycelium 
very  poorly  developed  or  not  developed  at  all,  leaving  slimy  layer  exposed; 
substratum  about  the  same  color  as  the  spores. 

Hab.  Often  on  Pisum  sativum,  seldom  on  underground  part  of  stem 
of  Solanum  tuberosum,  in  Germany,  and  cause  of  fruit  rot  of  Solarium 
lycopersicum  in  Germany  and  in  the  United  States. 


Fig.  7. —  Fusarium  falcalurn.  a,  Pscudopionnolal  conidia,  b,  chlamydospores  in  mycelium 
and  in  spore,  from  119-days-old  culture  on  hard  lima-bean  agar  with  2  per  cent  glucose; 
c,  chlamydospores,  d,  pseudopionnotal  conidia,  from  71-days-old  culture  on  red  raspberry  cane 
plug;  E,  pseudopionnotal  conidia  from  42-days-old  culture  on  potato  stem  plv^ 


Differs  from  F.  gibbosum  mainly  in  having  parabolic  dorsal  curve  and 
typically  exposed  pseudopionnotes;  also  in  considerably  longer  conidia. 

The  organism  was  not  isolated  by  the  writer,  but  the  culture  was  obtained 
through  the  courtesy  of  Dr.  Wollenweber.  The  writer's  cultural  observa- 
tions in  regard  to  septation  and  size  of  spores  of  this  organism  on  various 
media  are  as  follows: 


(only  a  few  measured) 


On  sUghtly  acidified  hard  potato  agar,  culture  twenty-four  days  old: 
Conidia:    3-septate,  3  per  cent,  28-42  x  3.5-4/x 
4-septate,  9  per  cent,  33-42  x  3.5-4/x 
5-septate,  77  per  cent,  50  x  4.5  (43-58  x  4-5.3) )U 
6-septate,  10  per  cent,  54  x  5  (50-60  x  4.8-5.3)^ 
7-septate,  1  per  cent,  about  60-70  x  4.8-5.3^1 


FusARiA  OF  Potatoes  137 

On  red  raspberry  cane  plug,  culture  seventy-one  days  old: 
Conidia:     3-septate,  2  per  cent 
4-septate,  3  per  cent 

5-septate,  90  per  cent,  43  x  4.6  (36^9  x  4-5.2) m 
6-septate,  5  per  cent,  46x4.8  (43-53 x 4.3-5 .2) m 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  one  hundred 

and  nineteen  days  old: 

Conidia:     1-septate,  2.5  per  cent,  15  x  2.7ju  (only  two  measured) 
3-septate,  3  per  cent,  30  x  3.6  (10-44  x  3-4.7) m 
4-septate,  5  per  cent 

5-septate,  81  per  cent,  49  x  4.7  (42-55  x  4.3-5.2) /x 
6-septate,  6  per  cent,  51  x  4.9  (45-56  x  4.6-5.2) /x 
7-septate,  2.5  per  cent,  52  x  5.2  (47-58  x  5.2) /x 
8-septate,  exceptionally  rare,  58  x  5.4  (only  one  measured) 

On  hard  lima-bean  agar,  culture  eleven  days  old: 
Conidia:     0-septate,  rare 

2-septate,  2  per  cent 

3-septate,  30  per  cent,  30  x  3.6  (20-40  x  3-4.3) m 

4-septate,  5  per  cent 

5-septate,  62  per  cent,  54.5x4.5  (43-65  x  3.5-5.2) m 

6-septate,  1  per  cent,  64x4.8  (59-70  x  4.6-5.3) m 

7-septate,  rare,  same  as  6-septate 

Average  of  the  above  measurements : 
Conidia:     0-septate,  very  rare 

1-septate,  0.5  per  cent 
2-septate,  0.5  per  cent,  15  x  2.1  ix 
3-septate,  9.5  per  cent,  30  x  3.6/x 
4-septate,  5.5  per  cent 
5-septate,  77.5  per  cent,  49.1  x  4.56^ 
6-septate,  5.5  per  cent,  54  x  4.9m 
7-septate,  1  per  cent,  58x5.1/x 
8-septate,  very  rare,  58  x  5.4/x 

Averages  of  Appel  and  Wollenweber's  (1910:184)  measurements  are  as 
follows : 

Conidia:     5-septate,  46  x  4. 7iu 
6-septate,  49  x  'iAn 


138 


C.  D.  Sherbakoff 


The  measurements  of  the  writer  show  some  deviation  from  these,  but 
the  deviation  is  small  and  can  be  explained  entirely  by  the  fact  that  the 
writer's  measurements  were  taken  from  much  younger  cultures,  which 
usually  yield  somewhat  longer  conidia  than  those  produced  in  old  cultures. 


9.  Fusariuin  falcatimi  Ap.  et  Wr.  var.  fuscum  n.  var.  (Fig.  8;  PI.  vii, 
fig.  8) 

Conidia  with  from  ellipsoidal  to  parabolic  dorsal  curve,  conspicuously 
broader    in    the    middle,    prominently    pedicellate,    typically  5-septatp, 


Fig.  8. —  Fusarium  Jalcaium  var.  juscum.  a,  Pseudopionnotal  conidia,  b,  conidiophores, 
from  4-days-old  culture  on  hard  potato  agar;  c,  intercalary  chlamydospores,  d,  pseudopionnotal 
conidia,  from  W-days-old  culture  on  hard  bean  agar;  e,  cluMer  of  intercalary  chlamydospores 
from  99^ays-old  culture  on  potato  tuber  plug;  f,  intercalary  chlamydospores  in  long  chains, 
G,  conidia  with  and  without  chlamydospores,  from  176-days-old  culture  on  corn  agar;  h,  young 
and  old  chlamydospores,  k,  sporodochial,  l,  atrial,  conidia,  from  79-days-old  culture  on  red 
raspberry  cane  plug;  M,  intercalary  and  terminal  chlamydospores,  n,  aerial  conidia,  from  50- 
days-old  cidture  on  rye  straw;  v,  typical  conidium  from  a  large  sporodochium  of  29-days-old 
culture  on  hard  oat  agar 


45  X  4.6  (40-51  x  4.4-4.7)ju,  3-  and  4-septate  ones  also  present,  6-  and 
7-septate  rare,  8-septate  very  rare,  typically  in  conspicuous  plecten- 
chymic  or  aplectenchymic  sporodochia,  from  light  buff  and  honey  yellow 
to  buckthorn  and  cacao  brown,  on  potato  agar  rich  in  glucose;  chlamydo- 
spores intercalary,  always  present,  sometimes  by  their  abundance  and 
color  making  the  entire  medium  and  the  aerial  mycelium  of  a  dark  brown 
color;  aerial  mycelium  always  present,  high,  from  fine  to  medium  fine, 
more  or  less  loose,  hyaline  at  first,  later  becoming  from  tawny  olive  to 
brown;  color  of  substratum  on  agars  from  hyaline  to  that  of  the  spores. 


FusARiA  OF  Potatoes  139 

Hab.     On  rotted  tubers  of  Solarium  tuberosum,  New  York  State. 

Differs  from  F.  falcatum  mainly  by  large  sporodochia,  more  profuse 
chlamydospore  production,  well-developed  aerial  mycelium,  and  typical 
absence  of  pseudopionnotes. 

The  organism  was  isolated  only  once,  from  a  potato  tul)er  slightly  rotted 
near  the  stem  end,  which  was  received  from  a  potato  grower  in  New  York. 
The  measurements  of  conidia  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  four  days  old: 
Conidia:     0-  and  1-septate,  few,  very  young 

3-septate,  4  per  cent,  38x4.3  (35-42  x  4. 1^.7) M 
4-septate,  6  per  cent,  41.6x4.4  (35-44  x  4.1^.7)^ 
5-septate,  88  per  cent,  45.5  x  4.6  (40-49  x  4. 1-4.8) m 
6-  and  7-septate,  2  per  cent,  50-80  x5.5/i  (only  a  few  measured) 
The  largest  5-septate  conidium  observed  measured  67  x  5.8/x 

On  red  raspberry  cane  plug,  culture  seventy-nine  days  old: 
Conidia:     3-septate,  1  per  cent 
4-septate,  4  per  cent 
5-septate,  95  per  cent,  40x4.7  (31-48x4.3-5.2)//. 

On  hard  lima-bean  agar,  culture  ten  days  old: 
Conidia:     3-septate,  3  per  cent,  34  x  4.4  (19^0  x  3.1-4.7) fi 
4-septate,  6  per  cent 
5-septate,  91  per  cent,  45x4.4  (36-61  x 4^. 8) ju 

On  hard  oat  agar,  culture  twenty-nine  days  old,  from  a  sporodochium 
about  3  millimeters  in  diameter: 
Conidia:     3-septate,  2  per  cent 

4-septate,  5  per  cent 

5-septate,  93  per  cent,  51  x  4.6  (45-53  x  4.1-4.9)^ 

Average  of  the  above  measurements: 
Conidia:     3-septate,  2.5  per  cent,  36  x  4.3/i 
4-septate,  5  per  cent,  41.6x4.4/x 
5-septate,  92  per  cent,  45  x  4.6/i 
6-  and  7-septate,  0.5  per  cent 


140 


C.  D.  Sherbakoff 


10.  Fusarium  caudatum  Wr.  var.  Solani  n.  var.  (Figs,  Iz  and  9;  PI,  iv, 
fig.  7;  PI,  VI,  fig,  3) 

Conidia  with  from  parabolic  to  ellipsoid  dorsal  curve,  conspicuously 
broader  at  the  middle,  with  very  long,  narrow,  whiplike  apex,  prominently 
pedicellate,  typically  5-  to  7-septate;  measuring  on  the  average,  5-septate, 
48x4.6  (40-55  X  4.3-4.7)  M,  7-septate,  64.7x4.6  (57-69  x  4.4-4.8)  m; 
rarely  in  pseudopionnotes,  typically  in  small  aplectenchymic  sporodochia, 
tinted  from  cream-buff  to  cinnamon,  clay,  and  Saccardo's  amber  in  a 


Fig.  9. —  Fusarium  caudatum  var.  Solani.  a,  Pseudopionnotal  conidia,  b,  conidiophores, 
from  9-days-old  cidlure  on  slightly  acidified  hard  potato  agar;  c,  pseudopionnotal  conidia  from 
38-days-old  cidture  on  potato  stem  plug;  d  and  e,  chlamydosporcs  from  50-days-old  culture  on 
red  raspberry  cane  plug  (magnification  250  times);  f,  conidia  from  aerial  sporodochium  of  118- 
days-old  culture  on  hard  lima-hcan  agar  with  2  per  cent  glucose;  g,  cluster  of  chlamydospores, 
H,  aerial  conidia,  from  50-days-old  culture  on  rye  straw;  i,  sporodochial  conidia  in  oozing  drop  of 
liquid  from  9-days-old  culture  on  hard  lima-hcan  agar;  j,  aerial  conidia,  k,  intercalary  chlamydo- 
spores, from  69-days-old  culture  on  red  raspberry  cane  plug 


plate  culture  on  a  potato  hard  agar  rich  in  glucose;  chlamydospores 
intercalary,  always  present  in  greater  or  less  abundance;  aerial  mycelium 
very  well  developed,  high,  uniform,  medium  dense,  from  hyaline  when 
young  to  sepia  in  old  cultures,  mostly  from  brownish  to  dresden  brown; 
substratum,  on  potato  agar  rich  in  glucose,  from  pinkish  buff  when  young 
to  ochraceous  tawny  and  snuff  brown  shaded  to  sepia  in  very  old  cultures, 
Hab,  On  superficial  dry-rot  spots  on  tubers  of  Solatium  tuberosum, 
Atlanta,  New  York. 


FusARiA  OF  Potatoes  141 

Differs  from  F.  caudatum  Wr.  (see  Wollenweber  1914:262-263,  PI.  xvi, 
fig.  m)  mainly  by  broader  eonidia,  whicli  in  the  latter  organism  average 
only  from  3  to  4.5/i  in  diameter. 

The  organism  was  twice  isolated,  in  1912  and  in  1913,  from  superficial 
dry  rot  of  potato  tubers  collected  at  Atlanta,  New  York.  The  measure- 
ments of  eonidia  on  different  media  are  as  follows: 

On  red  raspberry  cane  plug,  culture  sixty-nine  days  old: 
Conidia:     3-septate,  10  per  cent,  30  x  4  (26-35  x  3.5-4.5) m 
4-septate,  5  per  cent,  34  x  4.4  (32-40  x  4^.8) ju 
5-septate,  85  per  cent,  40  x  4.8  (33-55  x  4-5.4) /x 

On  slightly  acidified  hard  potato  agar,  culture  nine  days  old: 
Conidia:     3-septate,  1  per  cent,  about  38  x  4/i  (only  a  few  measured) 
4-septate,  8  per  cent,  about  40  x  4.2;u  (only  a  few  measured) 
5-septate,  43  per  cent,  55  x  4.3  (38-69  x  3.5-5.9) m 
6-septate,  27  per  cent,  65x4.4  (55-84  x  4. 1-5.3) ^u 
7-septate,  21  per  cent,  69  x  4.4  (60-85  x  4. 1-5.9) yu 
8-septate,  very  rare 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  one  hundred 

and  eighteen  days  old: 

Conidia:     4-septate,  1  per  cent 

5-septate,  29  per  cent,  46  x  4.7  (43-59  x  4.3-5.2) /x 
6-septate,  32  per  cent,  53  x  4.8  (48-60  x  4.3-5)  m 
7-septate,  37  per  cent,  57x4.8  (50-62  x  4.7-5)  m 
8-septate,  1  per  cent,  61  x  5iu  (only  one  measured) 

On  hard  lima-bean  agar,   culture  nine  days  old: 
Conidia:     5-septate,  55  per  cent,  52  x  4.5  (45-61  x  4-4.8) /x 
6-septate,  35  per  cent,  65  x  4.7  (55-71  x  4.3-4.8)/t 
7-septate,  10  per  cent,  68x4.7  (58-78x4.3-4.8)/* 

Average  of  the  above  measurements: 
Conidia:     3-septate,  3  per  cent,  34  x  4/i 
4-septate,  3.5  per  cent,  37  x  4/i 
5-septate,  53  per  cent,  48  x  4.6)L{ 
6-septate,  23.5  per  cent,  58  x  4.6^t 
7-septate,  17  per  cent,  64.7  x  4.6/i 
8-septate,  rare,  61  x  5m  (only  one  measured) 


142  C.  D.  Sherbakoff 

V.  Section  Roseum  Wr.  (emended),  Phytopath.  3:32,  fig.  1  n,  1913 
Conidia  broad  ellipsoid,  typically  of  an  even  diameter  for  a  consider- 
able part  of  their  length,  comparatively  narrow  (from  3.6  to  4.3/x  in  aver- 
age diameter),  always  very  gradually  attenuate  toward  both  ends,  conidia 
of  all  fruiting  forms  of  the  same  shape  and  type;  true  chlamydospores 
always  absent;  on  agars  rich  in  glucose,  from  honey  yellow  and  morocco 
red  to  Eugenia  red,  sometmies  nearly  hyaline. 

11,  Fusarium  acuminatum  Eli.  et  Ev.  emend.  Wr. 

Cf.  Wollenweber,  H.  W.,  Journ.  Agr.  Research  2:269-270,  PI.  xvi, 
fig.  G.  1914.  Fusarium  acuminatum  Ell.  et  Ev.,  Proc.  Acad.  vSci.  Phila. 
1895:441.  Saccardo,  Syll.  Fung.  14:1125-1126.  1899.  Wollenweber's 
diagnosis  (page  269  of  reference  cited)  is  as  follows: 

"  Conidia,  scattered,  in  sporodochia  or  in  pionnotes,  orange  in  mass. 
Conidia  average  as  follows:  5-septate,  40  to  70  by  3  to  4.5yu;  4-septate 
(less  common),  30  to  60  by  3  to  4.5/1;  3-septate,  20  to  45  by  2.75  to  4.25^. 
Conidia  of  0-,  1-,  2-,  6-,  and  7-septations  are  occasionally  found.  Sub- 
normal small  conidia  may  be  mistaken  for  conidia  of  the  section  Discolor, 
but  normal  sporodochia  develop  on  repeatedly  whorl-like  branched  conidio- 
phores,  giving  the  characteristic  conidia  of  the  section  Roseum.  The 
conidia  show  in  side  view  hyperbolic  or  parabolic  curves,  in  contrast 
to  Fusarium  metacroum  App.  and  Wollenw.,  the  conidia  of  which  are 
as  a  rule  more  nearly  straight.  Blue  globose  sclerotia,  50-70/i  thick, 
occur  and  form-a  striking  contrast  to  the  carmine  plectenchymatic  thallus 
on  starchy  media,  such  as  steamed  potato  tubers.  Both  blue  and  car- 
mine are  basic  modifications  of  the  fungus,  while  yellow  (on  rice)  is  the 
acid  one,  turning  blue  to  purple  violet  with  the  addition  of  an 
alkali. 

"  Habitat.  Occurs  on  partly  decayed  plants,  especially  on  stems, 
roots,  and  tubers,  also  on  fruits.  Found  on  Solanum,  Ipomoea,  Fagus 
(beech  nuts),  and  Impatiens  balsarnina  in  the  United  States  of  America." 

Ellis  and  Everhart's  description  is  incomplete,  but  Wollenweber  says 
(on  page  270  of  reference  cited)  that  he  "  found  this  fungus  so  widely 
distributed  on  potato  stems  in  the  New  England  States  that  he  feels 
justified  in  identifying  it  as  Fusarium  acuminatum."  The  writer  did 
not  study  this  fungus. 


FusARiA  OF  Potatoes 


143 


12.  Fusarium  metacroum  Ap.  et  Wr.  (Fig.  10;  PL  vii.  fig.  5) 
Appel,   0.,  and  Wollenweber,  H.   W.,  Arb.  K.  biol.  Anst.  Land-  u. 
Forstw.  8:132-141;  PI.  i,  figs.  Ill  to  118;  PL  iii,  fig.  8.     1910. 

Conidia  broad,  ellipsoid,  more  or  less  pointed  at  apex,  seldom  promi- 
nently pedicellate,  typically  5-septate,  53x4.1  (43-65  x  3.8-4.3) /x,  often 
3-  or  4-septate,  seldom  0-  to  2-,  rarely  6-,  exceptionally  up  to  12-septate, 
in  minute,  more  or  less  converging,  sporodochia  forming  exposed  pseudo- 
pionnotes,  from  Corinthian  red  to  clay  color,    typically  from  dragon's- 


FiG.  10. —  Fiisarium  metacroum.  Pseudopionnolal  conidia:  a,  from  65-days-old  culture  on 
rye  grain:  b,  from  10-days-old  cultwre  on  hard  lima-bean  agar;  c,  fro7n  8-days-old  culture  on 
hard  lima-beqn  agar  with  2  per  cent  glucose;  d,  from  113-days-old  culture  on  potato  stem  plug; 
E  and  F,  from  23-day s-old  culture  on  red  raspberry  cane  plug;  i  and  j,  from  11 -days-old 
culture  on  slightly  acidified  hard  potato  agar;  k,  from  66-day  s-old  culture  on  rye  grain.  G  and 
H,  Conidiophores  from  23-days-old  culture  on  red  raspberry  cane  plug 


blood  red  to  brick  red;  chlamydospores  absent;  aerial  mycelium  typically 
absent;  substratum  from  madder  brown  and  brazil  red  to  russet  color; 
conidia  often  densely  granulate  with  indistinct  septation. 

Hab.  On  grains  of  Triticum  vulgaris  in  Germany  and  on  rotted  tubers 
of  Solanum  tuberosum  in  New  York  State. 

The  organism  was  isolated,  together  with  F.  diver sis-porum,  from  a  rotted 
tuber  from  Long  Island.  The  two  fungi  were  growing  together,  and 
in  the  original  culture  the  mixture  appeared  to  be  a  pink  Fusarium.  The 
fungi  were  separated  by  dilution  and  remained  very  distinct  from  each 


144  C.  D.  Sherbakoff 

other.     F.  metacroum  isolated  by  the  writer  is  in  all  respects  identical 
with  the  originally  described  organism. 

The  measurements  of  the  conidia  from  the  original  culture  when  grown 
on  various  media  are  as  follows: 

On  red  raspberry  cane  plug,  culture  twenty-three  days  old : 

Conidia:     3-septate,  42  per  cent,  46  x  3.2  (35-56  x  2.6-4.1)m 

4-septate,  28  per  cent,  50  x  3.5  (40-62  x  2.9-4.1) m 

5-septate,  30  per  cent,  50  x  3.8  (45-63  x  3.3-4.3) m 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  eleven  days 
old: 

Conidia:     3-septate,  8  per  cent 
4-septate,  7  per  cent 

5-septate,  75  per  cent,  54  x  4.1  (35-62  x  3.5-5.7))U 
6-septate  and  more,  10  per  cent,  the  largest  spore  12-septate, 
91  X  5.3m 

On  slightly  acidified  hard  potato  agar,  culture  eight  days  old: 
Conidia:     3-septate,  15  per  cent 
4-septate,  15  per  cent 
5-septate,  70  per  cent,  65  x  4.2  (55-73  x  3.8-4.8) m 

On  potato  tuber  plug,  culture  ninety-eight  days  old: 
Conidia:     1-septate,  5  per  cent,  19-x  3  (14-21  x  2.7-3.5) m 
2-septate,  few 

3-septate,  10  per  cent,  36  x  3.8  (28-43  x  3.5-4.2) m 
4-septate,  30  per  cent,  46  x  3.9  (36-51  x  3.5-4.7) m 
5-septate,  55  per  cent,  50  x  4  (42-63  x  3.5-4.4) ^ 

On  potato  stem  plug,  culture  one  hundred  and  thirteen  days  old: 
Conidia:     3-septate,  25  per  cent,  36  x  3.7  (33-39  x  3.4-3.9) /i 

4-septate,  20  per  cent,   about  39  x  4^  (only  a  few  measured) 
5-septate,  55  per  cent,  43x4  (38-47  x  3.5-4.2) /i,  the  longest 
5-septate,  63  x  3.85)u 

On  whole  steamed  potato  tuber,  culture  thirty-eight  days  old: 
Conidia:     3-septate,  40  per  cent,  42  x  3.9  (37-53  x  3.5-4.1)/x 
4-septate,  35  per  cent,  45  x  4.1^ 
5-septate,  25  per  cent,  54  x  4.3  (47-63  x  3.7-4.8) /z 


FusARiA  OF  Potatoes  145 

On  rye  grain,  culture  sixty-five  days  old: 

(1)  From  a  sliiny  heap  of  conidia  1  millimeter  in  diameter 
Conidia:     3-septate,  27  per  cent,  43  x  3.8  (31-49  x  2.9-4.7)/i 

4-septate,  11  per  cent,  44  x  4.1  (40-63  x  2.6^.8) /x 
5-septate,  62  per  cent,  54.5  x  4.1  (43-67  x  3-5.2)  m 

(2)  From  a  minute,  semi-dry  fleck  of  conidia,  culture  sixty-six  days  old 
Conidia:     0-septate,  2  per  cent 

1-septate,  3  per  cent,20x3.5 1  /     ,        ^  ,n 

2-septate,  3  per  cent,  23x3.9/  ^^^^^^  ^  ^^^  measured) 
3-septate,  65  per  cent,  32  x  3.9  (22^7  x  3.5^.4)^ 
4-septate,  12  per  cent,  43  x  4.1  (38-48  x  3.5-4.4)/i 
5-septate,  15  per  cent,  45x4.3  (38-48  x  3.5-4.7) m,  the  largest 
53  X  5.25m 
On  hard  lima-bean  agar,  culture  ten  days  old: 
Conidia:     3-septate,  6  per  cent,  48  x  3.7 fx  (only  three  measured) 
4-septate,  4  per  cent 
5-septate,  90  per  cent,  61  x  3.9  (43-68  x  3.5-4.1)/x 

Average  of  the  above  measurements: 
Conidia:     0-  to  2-septate,  rare 

3-septate,  26  per  cent,  40.4  x  3.7/x 
4-septate,  19  per  cent 
5-septate,  54  per  cent,  53  x  4.1/i 
6-  and  7-septate,  1  per  cent 

The  averages  of  Appel  and  Wollenweber's  measurements  are  as  follows: 
Conidia:     3-septate,  9  per  cent,  39  x  3.9^ 
4-septate,  14  per  cent,  43  x  4.2^ 
5-septate,  76  per  cent,  53  x  4.3^ 
6-septate,  1  per  cent,  63  x  4.6^ 

13.  Fusarium  metacroum  Ap.  et  Wr.  var.  minus  n.  var.  (Fig.  11) 

Conidial  type  as  in  F.  metacroum,  5-septate  conidia  54  x  3.6  (46-60  x 
3.4-3.9)/x. 

Hab.     On  stem  of  Solanum  tuberosum,  New  York  State. 

Differs  from  F.  metacroum  by  narrower  conidia,  often  distinct  plecten- 
chymic  substratum,  and  swellings  in  hyphse  very  similar  to  true  chlamydo- 
spores. 


146 


C.  D.  Sherbakoff 


The  organism  was  isolated  only  once,  from  a  half-dead  stem  of  potato 
plant  at  Atlanta,  New  York,  from  a  pseudopionnotal  spore  mass.  The 
measurements  of  the  conidia  produced  by  the  organism  on  various  media 
are  as  follows: 

On  red  raspberry  cane  plug,   culture  thirty-one  days  old: 
Conidia:     1-septate,  0.5  per  cent,  20  x  2.5/x 
2-septate,  very  few 

3-septate,  46.5  per  cent,  43  x  2.8  (23-53  x  2.3-3.5) /x 
4-septate,  31  per  cent,  48  x  3.2  (40  60  x  2.3-3.5) /x 
5-septate,  22  per  cent,  52  x  3.4  (42  60  x  2.9-4)m 
6-septate,  rare,  61  x  3.4;u  (only  one  measured) 


Fig.  11. —  Fusarium  metacroum  var.  minium,  a,  Conidia  from  18-d.ays-oId  culture  on  hard 
lima-bean  agar;  b,  conidia  from  the  original  specimen,  potato  stem,  August  7,  1912;  c,  chlamydo- 
spore-like  structures  of  hyphce  from  26-  and  176-days-old  cultures  on  corn  agar;  d,  conidiophore 
from  the  original  specimen,  potato  stem,  August  7,  1912;  e,  conidiophores  frotn  31-days-old 
ctdture  on  red  raspberry  cane  plug;  f,  conidia  producing  numerous  conidiophores  from  10-day s- 
old  culture  on  hard  lima-bean  agar;  g,  normal  conidia  from  10-day s-old  culture  on  hard  lima- 
bean  agar;  h,  conidiophores  from  31-days-old  culture  on  red  raspberry  cane  plug;  i,  conidia 
from  31-days-old  culture  on  red  raspberry  cane  plug.     All  conidia  are  from  pseudopionnotes 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  eight  days  old : 
Conidia:     3 -septate,  17  per  cent 
4-septate,  17  per  cent 
5-septate,  66  per  cent,  60  x  3.6  (53-65  x  3-4.2)/i 

On  potato  tuber  agar,   culture  ninety-eight  days  old: 
Conidia:     0-septate,  5  rt'^r  ppnf 


per  cent 
1-septate,  5  per  cent 
2-septate,  rare 
3-septate,  20  per  cent 


o-ocpuiit?,  ^u  per  ueiu.,  34x3.5  (26-39  X  3-4) /x 
4-septate,  30  per  cent,  42  x  3.8  (36-48  x  3.5-4. 1)^ 
5-septate,  40  per  cent,  46  x  3.9  (40-54  x  3.5-4. l)/i 


FusARiA  OF  Potatoes  147 

On  rye  grain,  culture  sixty-five  days  old: 
Conidia:     3-septate,  20  per  cent,  41  x  3.2  (36^6  x  2.9-4)/x 
4-septate,  17  per  cent,  48  x  3.3  (40-54  x  2.9-4)m 
5-septate,  63  per  cent,  52x3.7  (40-60  x  3-4.1) m 
On   hard   lima-bean   agar,    culture   ten   days   old: 
Conidia:     1-septate,  very  few 

3-septate,  11  per  cent,  50x3.3  (29-61  x  3-3.7)m 

4-septate,  4  per  cent 

5-septate,  85  per  cent,  60x3.5  (45-67  x  3.1-4)^ 

Average  of  the  above  measurements: 
Conidia:     0-  to  2-septate,  2  per  cent,  20  x  2.5/x 
3-septate,  23  per  cent,  42  x  3.2/x 
4-septate,  20  per  cent 
.  5-septate,  55  per  cent,  54  x  3.6// 
6-septate,  very  rare,  61  x  3.4// 

14.  Fusarium  suhulatiim  Ap.  et  Wr.  (Fig.  Iw;  Fig.  12,  g  to  j;  PI.  ii, 
fig.  11;  PI.  VII,  fig.  4) 

Appel,  0.,  and  Wollenwelier,  H.  W.,  Arb.  K.  biol.  Anst.  Land-  u.  Forstw. 
8:118-132,  PI.  II,  figs.  65  to  87.  1910.  Wollenweber,  H.  W.,  Phytopath. 
3:32,  fig.  In.    1913. 

Conidia  slightly  elliptically  curved,  typically  of  nearly  even  diameter 
for  the  greater  part  of  their  length,  very  gradually  attenuate  toward  both 
ends,  shghtly  pedicellate,  typically  5-septate,  58  x  3.64  (48-65  x  3.4-3. 85)/t, 
usually  in  numerous,  sometimes  converging  sporodochia  (j  to  1  millimeter 
in  diameter),  produced  near  substratum  and  lower  aerial  mycelium, 
from  pink-flesh  to  apricot-bufT  and  from  coral  red  to  brick  reel  in  color, 
with  darker  shades  in  old  moist  cultures;  chlamydospores  absent;  aerial 
mycelium  typically  present,  at  first  hyaline,  then  testaceous  color  and 
other  hues  of  red;  on  various  agars  from  vinaceous  tawny  and  madder 
brown  to  pomegranate  purple  and  Eugenia  red. 

Hab.  A  cosmopolitan  saprophyte,  of  very  wide  occurrence  on  dead 
substrata,  in  soil  and  water,  also  parasitic  on  cereals  and  on  tubers  of 
Solanum  tuberosum. 

The  organism  was  twice  isolated  by  the  writer  from  rotted  potato 
tubers,  and  the  strains  were  compared  with  a  culture  of  the  originally 
described  organism  obtained  through  the  courtesy  of  Dr.  Wollenweber 


148 


C.  D.  Sherbakoff 


and  proved  to  be  identical.     The  writer's  measurements  of  conidia  of 
the  original  strain  are  as  follows: 

On  red  raspberry  cane  plug,  culture  twenty-seven  days  old: 
Conidia:     3-septate,  10  per  cent,  55  x  2.9 fx 

4-septate,  20  per  cent,  60.4  x  3  (54-76  x  2.6-3.5) m 
5-septate,  70  per  cent,  65x3.4  (57-76  x  2.6-4.  1)m 

On  potato  tuber  plug,  culture  ninety-nine  days  old: 
Conidia:     0-  to  2-septate,  none  to  very  few 

3-septate,  35  per  cent,  33  x  3.7  (27-40  x  3-4) /x 
4-septate,  20  per  cent,  38  x  3.7  (32-42  x  3-4. 1)^ 
5-septate,  45  per  cent,  48  x  3.85  (42-58  x  3.5-4. 1)^ 
6-septate,  rare,  57  x  4/x  (only  one  measured) 


Fig.  12. —  a-f,  Fusarium  subulatum  var.  brevius:  a,  Conidia,  b,  coiiidiophorc,  from  small 
sporodochium  of  31 -days-old  cidture  on  red  raspberry  cane  plug;  c,  sporodochial  conidia  from 
113-days-old  culture  on  potato  stem  plug;  d,  pseudopionnotal  conidia  from  38-days-old  culture 
on  whole  steamed  potato  tuber;  k,  sporodochial  conidia  from  65-days-old  culture  on  rye  straw; 
F,  aerial  conidia  from  10-days-old  culture  on  hard  lima-bean  agar. 

G-J,  F.  subulatum:  g,  Sporodochial  conidia  from  31 -days-old  cidture  on  red  raspberry  cane 
plug;  H,  semi-dry  conidia  from  sporodochium  of  38-days-old  culture  on  steamed  potato  tuber; 
I,  sporodochial  conidia  from  113-days-old  culture  on  potato  stem  plug;  J,  sporodochial  conidia 
from  65-days-old  culture  on  rye  grain 


On  potato  stem  plug,  culture  one  hundred  and  thirteen  days  old: 
Conidia:     3-septate,  5  per  cent,  about  35  x  3/x  (only  a  few  measured) 
4-septate,  4  per  cent 
5-septate,  91  per  cent,  54  x  3.6  (47-65  x  3.2-3.9) /x 

On   steamed   potato   tuber,    culture   thirty-eight   days   old: 
Conidia:     3-septate,  3  per  cent,  about  40  x  3.5^ 
4-septate,  8  per  cent,  about  48  x  3.6ju 
5-septate,  89  per  cent,  55  x  3.7  (37-63  x  3.5-3.9)m 
6-septate,  few,  same  measurement  as  5-septate 


FusARiA  OF  Potatoes  149 

On  rye  grain,  culture  sixty-five  days  old: 
Conidia:     3-septate,  4  per  cent,  52  x  3.4  (42-55  x  2.9-4) yit 

4-septate,  15  per  cent,  54  x  3.5  (42-67  x  2.9-4.1)/i 
5-septate,  81  per  cent,  64  x  3.7  (45-75  x  2.9-4.2)^ 

On  hard  lima-bean  agar,  culture  ten  days  old : 
Conidia:    0-septate,  rare 

2-septate,  very  rare 

3-septate,  11  per  cent,  45  x  3.1  (33-60  x  3-3. 5) m 

4-septate,  19  per  cent 

5-septate,  70  per  cent,  60  x  3.6  (53-67  x  3.1-4)/* 

9-septate,  rare,  69  x  5.7^  (only  one  measured) 

Average  of  the  above  measurements: 
Conidia:    0-septate,  none  to  rare 

1-  and  2-septate,  none  to  rare 
3-septate,  11  per  cent,  43.3  x  3.3/x 
4-septate,  15  per  cent 
5-septate,  74  per  cent,  58  x  3.64^ 
6-  to  9-septate,  none  to  rare 

The  averages  of  Appel  and  Wollenweber's  measurements  for  the  same 

organism  are  as  follows: 

Conidia:     1-septate,  rare 

3-septate   \  ^„  ,  /  36.5  x  3.86m 

.      ^,   ,       >  28  per  cent  <    ^,  ^     o  c 
4-septate    j  (51.5x3.5/i 

5-septate,  62  per  cent,  61  x  3.86)U 

6-septate,  9  per  cent,  69  x  4/i 

7-septate,  1  per  cent 

This  shows  the  5-septate  conidia  to  be  in  about  the  same  proportion 

and  of  about  the  same  size  as  found  by  the  writer. 

15.  Fusarium  suhulatum  Ap.  et  Wr.  var.  brevius  n.  var.  (Fig.  12, 
A  to  f;  pi.  II,  fig.  12;  PI.  vii,  fig.  3) 

Conidia  and  fruiting  forms  of  the  same  type  as  those  of  F.  suhulatum; 
chlamydospores  also  absent;  5-septate  conidia  average  50x3.8  (41-58  x 
3. 1-4.2) /x  in  size. 

Hab.     On  rotted  tuber  of  Solanum  tuberosum,  Ithaca,  New  York. 


150  C.  D.  Sherbakoff 

Differs  from  F.  suhulatum  Ap.  et  Wr.  mainly  in  shorter  conidia,  absence 
of  carmine  color  in  substratum,  and  high,  better-developed,  aerial 
mycelium. ^^ 

The  measurements  of  the  conidia  on  various  media  are  as  follows: 
On  red  raspberry  cane  plug,  culture  thirty-one  days  old: 
Conidia:     3-septate,  35  per  cent,  40  x  2.7  (29-49  x  2.3-3.3) m 
4-septate,  20  per  cent,  51  x  3  (45-53  x  2.3-3.4)/! 
5-septate,  45  per  cent,  55  x  3.1  (48-60  x  2.9-3.8) m 
On  potato  tuber  plug,  culture  ninety-nine  days  old  (in  general,  spores 
more  or  less  deteriorated): 
Conidia:     1-septate,  1  per  cent 

3-septate,  33  per  cent,  30  x  3.6  (21-42  x  3-4) ju 
4-septate,  20  per  cent,  36  x  3.9  (33-42  x  3.5-4.1)/x 
5-septate,  46  per  cent,  41  x  4  (35-48  x  3.5-4.1)/x 
6-septate,  rare,  43  x  4.1/i  (only  one  measured) 
On  potato  stem  plug,  culture  one  hundred  and  thirteen  days  old: 
Conidia:     3-septate,  67  per  cent,  34  x  3  (28-49  x  2.9-3.6) m 
4-septate,  20  per  cent,  42  x  3.3  (37-48  x  3-3.8) m 
5-septate,  13  per  cent,  44.6  x  3.4  (38^7  x  3-3.8))li 
On  whole  steamed  potato  tuber,  culture  thirty-eight  days  old: 
Conidia:     3-septate,  25  per  cent,  37  x  3.8  (31^2  x  3.5-4) m 
4-septate,  35  per  cent,  43  x  4  (36-49  x  3.5-9.2) /x 
5-septate,  40  per  cent,  47  x  4.1  (40-56  x  3.5-4.4)m 
6-septate,  few,  52  x  4.4  (only  a  few  measured) 
On  rye  grain,  culture  sixty-five  days  old: 
Conidia:     3-septate,  16  per  cent,  42  x  4  (36^9  x  3.5-4.3)/x 
4-septate,  17  per  cent,  45  x  4.1  (36-54  x  3.5-4.3)/* 
5-septate,  67  per  cent,  51  x  4.2  (43-58  x  3.7-4.7) /z 
On  hard  lima-bean  agar,  culture  ten  days  old: 
Conidia:     0-septate,  very  rare 
1-septate,  very  rare 
2-septate,  very  rare 

3-septate,  24  per  cent,  41  x  3.3  (36-48  x  3-3.5) /i 
4-septate,  20  per  cent 
5-septate,  56  per  cent,  52 x  3.9  (42-59  x  3.2-4.1)/^ 

"  This  grows  straight  up  and  out  from  tho  point  of  inoculation  in  a  plate  culture  on  potato  agar  in  the 
first  week  of  its  growth,  while  the  aerial  mycelium  in  F  suhulatum  is  always  of  a  more  or  less  loose,  feltlike 
character,  uniformly  medium  short  over  the  surface  of  the  colony. 


FusARiA  OF  Potatoes  151 

On  medium  potato  agar,  culture  ten  days  old : 
Conidia:     3-septate,  9  per  cent,  about  45  x  3.3  (only  two  measured) 
4-septate,  3  per  cent 
5-septate,  88  per  cent,  58  x  3.5  (47-64  x  3.1-4)^ 

Average  of  the  above  measurements: 
Conidia:    0-  to  2-septate,  absent  or  more  or  less  rare 
3-septate,  30  per  cent,  38.4  x  3.4/i 
4-septate,  19  per  cent 
5-septate,  51  per  cent,  49.8  x  3.76ai 
6-septate,  absent  to  1  per  cent,  47.5  x  4.25/x 

16    Fusarium  effusum  n.  sp.  (Fig.  13;  PI.  vii,  fig.  6) 

Conidia  gradually  pointed  toward  apex,  distinctly  but  not  prominently 
pedicellate,  typically  5-septate,  50x4.3  (44.5-57x3.9-4.5)//,  often  3-  to 
7-,  seldom  1-  to  2-septate;  single  or  in  indistinct  pseudopionnotes  and 
in  large  (on  oats,  wheat,  and  the  like,  about  |  centimeter  in  diameter) 
plectenchymic  sporodochia;  shape  of  conidia  of  nearly  the  same  type, 
in  all  stages  and  in  mass,  of  salmon  color  and  its  tints;  aerial  mycelium 
typically  well  developed,  though  on  an  agar  may  be  resupinate,  uniform, 
without  any  differentiated  tufts  or  strands,  from  white  to  cream  and 
tints  of  salmon  color;  substratum,  on  glucose  agar,  from  chamois  to 
morocco  red,  and  on  glucose-free  agar,  from  colorless  to  Eugenia  red; 
typical  spore  germination  by  straight,  unbranched  tubes  (Fig.  13  j); 
mycelium  in  young  colony  (Fig.  13  h)  typically  composed  of  nearly  straight, 
sparse  in  number,  and  more  or  less  regular,  branches. 

Hab.     On  dry  tubers  of  Solanum  tuberosum,  Minnesota. 

Latin  description. — Conidiis  gradatim  in  apicem  acutis,  distincte  sed 
non  insignite  pedicellatis,  typice  5-septatis,  50  x  4.3  (44.5-57  x  3.9-4.5)/x, 
saepe  3-7-,  raro  1-2-septatis;  continuis  vel  in  indistinctis  pseudopionno- 
tibus  atque  in  magnis  (in  avena,  tritico,  etc.,  circa  |  cm.  diam.)  plecten- 
chymicis  sporodochiis ;  conidiis  prope  eodem  in  omnibus  gradibus  typo, 
in  totum  "salmon-color"  (R);  aerio  myceho  typice  plene  maturo,  sed  in 
agare  interdum  resupinato,  uniformi,  sine  ullis  discretis  cristis  aut  fibris, 
ex  albo  "cream  color"  (R)  "sahiion  color"  (R)  vel  simih colore ;  substrato 
in  agare  glucoso  e  "chamois"  (R)  "morocco  red"  (R),  in  agare  non 
glucoso  ex  hyalino  "Eugenia  red"  (R);  sporis  per  rectos  et  non  ramosos 
cylindros  typice  germinatis  (Fig.  13  j);  mycelio  in  colonia  juveni  ex  prope 
rectis,  sparsis,  plus  minusve  regularibus  ramis  composito. 


152  C.  D.  Sherbakoff 

Hab.  In  tuberibus  aridis  Solani  tuberosi,  Minnesota,  Amer.  bor. 

The  fungus  was  isolated  in  association  with  F.  Solani  from  an  old  rotted 
potato  tuber  from  Minnesota.  Measurements  of  conidia  from  cultures 
on  different  media  are  as  follows: 


Fig.  13. —  F%isarium  effusum.  a,  Pseudopionnotal  conidia  from  7 -days-old  culture  on  hard 
lima-bean  agar  ivith  2  per  cent  glucose;  b,  pseudopionnotal  conidia  from  13-days-old  culture 
on  hard  lima-bean  agar  (rare  forms  of  conidia  shown  at  the.  center);  c,  pseudopionnotal  conidia, 
D,  conidiophores,  from  9-days-old  culture  on  medium  potato  agar;  e,  sporodochial  conidia  from 
24-days-old  culture  on  potato  tuber  plug;  f,  sporodochial  conidia  from  76-days-old  culture  on 
red  raspberry  cane  plug;  g,  typical  sporodochial  conidia  from  107 -days-old  culture  on  potato 
stem  plug;  h,  character  of  colony  growth  [magnification  80  times),  i , sporodochial  conidia,  from 
SJf-days-old  culture  on  rye  grain;  j,  character  of  spore  germination  from  potato-decoction  hanging 
drop  in  van  Tieghem  cell  {magnification  80  times);  k,  l,  conidiophores,  M,  normal  conidia, 
N,  anastomosed  conidia,  o,  conidiophores,  from  36-days-old  culture  on  corn  meal 

On  slightly  acidified  hard  potato  agar,  culture  ten  days  old;   conidia 

from  pseudopionnotes : 

Conidia:     2-septate,  rare 

3-septate,  50  per  cent,  34  x  4.1  (28-47  x  3-4.7) /x 

4-septate,  10  per  cent,  45  x  4.2/x 

5-septate,  40  per  cent,  50  x  4.5  (42-65  x  3.5-5.3)/* 


FusARiA  OF  Potatoes  153 

On  red  raspberry  cane  plug,  culture  seventy-six  days  old;  conidia  from 

a  sporodochium: 

Conidia:     3-septate,  35  per  cent,  42  x  3.3  (32-i8  x  2.7-4) m 
4-septate,  15  per  cent,  47  x  3.6  (42-53  x  3.2-4.3) m 
5-septate,  50  per  cent,  49  x  3.9  (38-58  x  3.2-4.4) ^ 
6-septate,  very  rare 

On  hard  lima-bean  agar,  2  per  cent  glucose,  culture  seven  days  old; 

conidia  from  mycelium: 

Conidia:     1-septate,  1  per  cent 
2-septate,  5  per  cent 

3-septate,  19  per  cent,  39  x  4.2  (28-50  x  3.9-4.8)/* 
4-septate,  10  per  cent 

5-septate,  60  per  cent,  57  x  4.3  (52-72  x  4-5.3)  m 
6-septate,  5  per  cent,  62  x  4.7  (49-72  x  4.3-5.3)m 
7-septate,  rare,  72  x  4.3ju  (only  one  measured) 
8-septate,  exceptional,  87.5  x  5.8 ^  (only  one  measured) 

On  potato  tuber  plug,  culture  twenty-four  days  old;  conidia  from  a 

sporodochium: 

Conidia :     0-septate 

1-septate,  2  per  cent 

2-septate,  1  per  cent 

3-septate,  12  per  cent,  32  x  4.3  (28-36  x  3.9-4.4)/* 

4-septate,  21  per  cent,  34  x  4.5  (29-41  x  4.1-4.7)/* 

5-septate,  61  per  cent,  44.5  x  4.5  (35-51  x  4. 1-4.8) /x 

6-  and  7-septate,  3  per  cent,  53  x  4.7  (49-54  x  4.3-5.2)/* 

On  potato  stem  plug,  culture  one  hundred  and  seven  days  old;  conidia 
from  a  sporodochial  mass  (spores  mostly  with  deteriorated  ends) : 
Conidia:     3-septate,  5  per  cent 

4-septate,  15  per  cent 

5-septate,  80  per  cent,  49  x  4  (35-63  x  3.5-4.7)/* 

On  hard    lima-bean   agar,    culture  ten   days  old;  conidia  from  aerial 
mycelium : 
Conidia:     1-septate,  rare,  21  x  3.1/*  (only  one  measured) 

3-septate,  11  per  cent,  36.2  x  4  (28^2  x  3.1^.8)/* 


154  C.  D.  Sherbakoff 

4-septate,  4  per  cent 

5-septate,  81  per  cent,  50.5  x  4.5  (38-60  x  3.9-4.8)At 
6-septate,  4  per  cent,  56  x  4.7  (48-04  x  4.4-5.2) ju 
7-septate,  rare,  62  x  5.2/i  (only  one  measured) 

On  the  same  medium  as  above,  culture  sixteen  days  old;  conidia  from 
aerial  mycelium  and  indistinct  pseudopionnotes : 
Conidia:     1-septate,  1  per  cent,  18  x  3.5/i  (only  a  few  measured) 
2-septate,  1  per  cent,  24  x  4/i  (only  a  few  measured) 
3-septate,  12  per  cent,  33  x  4  (21-44  x  2.9-4.8)  m 
4-septate,  6  per  cent 

5-septate,  71  per  cent,  50  x  4.3  (38-62  x  3.5-4.7) m 
6-septate,  7  per  cent,  60  x  4.7  (55-64  x  4.5-4.8) /z 
7-septate,  2  per  cent,  62  x  4.7  (59-65  x  4.4-4.8) m 

Average  of  the  above  measurements: 
Conidia:     1-septate,  less  than  1  per  cent,  18  x  3.5/i 
2-septate,  2  per  cent,  24  x  4.0^ 
3-septate,  20  per  cent,  36  x  4.0)u 
4-septate,  12  per  cent 
5-septate,  63  per  cent,  50  x  4.3m 
6-  and  7-septate,  3  per  cent,  68  x  4.8/x 

F.  ejfusum,  especially  in  its  sporodochial  stage,  much  resembles  the  fol- 
lowing other  species:  F.  subulatum,  F.  lucidum,  F.  biforme,  F.  diver- 
sisporum.  From  F.  suhulatum  it  can  be  at  once  distinguished  by  the  diam- 
eter of  the  conidia  and  by  the  larger  size  of  sporodochia.^"  From  F. 
lucidum  it  differs  primarily  by  the  common  presence  of  6-  and  7-septate 
conidia,  which  are  absent  in  F.  lucidum,  and  by  denser  red  substratum  than 
that  of  the  latter  species.  From  F.  biforme  it  differs  mainly  by  absence 
of  the  long,  9—  or  more  septate,  conidia  in  pseudopionnotes,  and  also  by 
absence  of  arthrosporial  conidial  form,  the  pluriseptate  conidia  and  arthro- 
sporial  conidia  on  aerial  mycelium  being  more  or  less  common  in  F.  bi- 
forme. From  F.  diversisporum  it  differs  by  absence  of  arthrosporial  co- 
nidia, which  are  typically  produced  on  aerial  mycelium  of  F.  diversisporum. 

*"  Sporodoohia  of  F.  suhulatum  as  a  rule  are  small,  but  on  whole  .steamed  potato  tubers  they  may  be  as 
large  as  those  of  F.  effusum. 


FusARiA  OF  Potatoes 


155 


17.  Fusarium  truncatum  n.  sp.  (Figs.  1,  Ci  to  Ei,  and  14;  PI.  vii,  fig.  1) 
ConicUa  typically  sickle-shaped,  gradually  pointed  toward  the  apex, 
slightly  broader  at  or  just  above  the  middle,  distinctly  pedicellate,  3-  to 
5-septate;  3-septate  averaging  35  x  3.7  (31.5^2  x  3.4-3.9)/i,  5-septate 
averaging  45  x  3.9  (43-48  x  3.4— 4.2) /i;  from  cinnamon  and  terra  cotta  to 
carmine-pomegranate  purple  in  color;  conidiophores  from  loose  to  dense, 
bushlike,  single  or  in  from  small  to  large  (up  to  |  centimeter  in  diameter) 
sporodochia;  aerial  mycelium  always  well  developed,  mostly  composed  of 
fine  but  macroscopically  distinct  threads,  from  white  to  slightly  carmine 
near  substratum;  color  of  substratum,  on  hard  potato  agar  rich  in  glucose, 


Fig.  14. —  Fusarium  truncatum.  a,  Sporodochial  conidia  from  60-days-old  culture  on  red 
rasphirry  cane  plug;  b,  aerial  conidia  Jrojn  13-days-old  culture  on  hard  potato  agar;  c,  aerial 
conidia  {some  with  distinctly  truncate  basal  cell)  from  H-days-old  culture  on  medium  potato 
agar;  t>,  conidiophore  from  13-days-old  culture  on  hard  potato  agar;  e,  sporodochial  conidia  from 
l/f-days-old  culture  on  medium  potato  agar;  f,  conidiophores  from  4''' -days-old  culture  on  potato 
tuber  plug;  g,  sporodochial  conidia  from  37-days-old  culture  on  hard  oat  agar;  h,  conidia  from 
aerial  mycelium  from  47-days-old  culture  on  potato  tuber  plug;  i,  conidiophore  from  J^-days-old 
colony  in  petri  dish  on  hard  potato  agar  with  10  per  cent  glucose 


varies  from  pale  cinnamon  and  diffuse  salmon  hues  to  corinthian  and 
brick  red,  more  or  less  distinctly  zonate. 

Hab.     On  rotted  tubers  of  Solmium  tuberosum,  New  York  State. 

Latin  description. — Conidiis  typice  falciformibus,  gradatim  in  apicem 
acutis,  paulo  latioribus  medio  vel  subinde  supra  medium,  distincte  pe- 
dicellatis  3-5-septatis;  3-septatis  plerumque  35x3.7  (31.5-42  x  3.4-3. 9)m, 
5-septatis  plerumque  45x3.9  (43-48  x  3.4-4. 2)/x;  e  "cinnamon"  (R) 
et  "terra  cotta"  (R)  "carmine"  (R)  et  "pomegranate  purple"  (R);  co- 


156  C.  D.  Sherbakoff 

nidiophoris  laxis  demum  dense,  fruticosis,  continuis  vel  in  parvis  magnisve 
(usque  ad  |  cm.  diam.)  sporodochiis;  aerio  mycelio  semper  plene  mature, 
ex  hyphis  subtilibus  sed  macroscopice  distinctis  composito,  ex  albo  paulum 
"carmine"  (R)  prope  substratum;  substrate  in  duro  agare  glucoso  Solani 
tuberosi  e  pallide  "  cinnamon  "  (R)  et  "  salmon  color  "  (R)  diffuse  "  Corinth- 
ian "  et  "  brick  red  "  (R),  plus  minusve  distincte  zonato. 
Hab.  In  tuberibus  putridis  Solani  tuberosi,  New  York,  Amer.  bor. 

Measurements  of  conidia  from  cultures  on  different  media  are  as  follows : 

On  slightly  acidified  hard  potato  agar,  culture  thirteen  days  old;  conidia 

from  aerial  mycelium: 

Conidia:     0-septate,  7  per  cent 
1-septate,  54  per  cent 
2-septate,  6  per  cent 

3-septate,  22  per  cent,  31.5  x  3.75  (21-45  x  3.1-4.1)^ 
4-septate,  4  per  cent,  40  x  4.1  (32-49  x  3.5-4.7) /x 
5-septate,  7  per  cent,  43  x  4.1  (33-53  x  3.9-4.7) /x 
6-septate,  rare,  45  x  4.5m  (only  two  measured) 

On  potato  tuber  plugs,  culture  forty-six  days  old;  conidia  from  a  sporo- 

dochium  2  millimeters  in  diameter: 

Conidia:     3-septate,  63  per  cent,  37  x  3.4  (27-49  x  3-3.6) m 
4-septate,  22  per  cent,  41  x  3.7  (40-45  x  3.5-4) ^ 
5-septate,  15  per  cent,  43  x  3.7  (40-45  x  3.5-4.  1)m 

On  red  raspberry  cane  plug,  culture  sixty  days  old;  conidia  from  a  sporo- 
dochium   about   2   millimeters   in   diameter: 
Conidia:     3-septate,  29  per  cent,  37  x  3.9  (28-41  x  3.5-4.2) /x 
4-septate,  31  per  cent,  40  x  3.9  (35-43  x  3.5-4.2) m 
5-septate,  40  per  cent,  44  x  4  (36-46  x  3.5^.5)// 

On  potato  stem  plug,  culture  eighty-three  days  old;  conidia  from  a 
sporodochium  about  1^  millimeters  in  diameter  (many  of  the  conidia  much 
deteriorated) : 
Conidia:     3-septate,  20  per  cent 

4-septate,  16  per  cent 

5-septate,  64  per  cent,  48  x  3.4  (44-51  x  3. 1-3.7) m 


FusARiA  OF  Potatoes  157 

On  soft  potato  agar,  plate  culture  fourteen  days  old;  conidia  from  thick 
pseudopionnotal  mass  near  the  inoculation  point: 
Conidia:     3-septate,  20  per  cent,  42  x  3.4  (35-51  x  3-3.9) m 

4-septate,  13  per  cent 

5-septate,  67  per  cent,  50  x  3.6  (43-65  x  3.1-3.9)m 

On  same  medium  as  above,  plate  culture  also;   conidia  from  a  small 

sporodochium  on  aerial  mycelium: 

Conidia:     0-septate,  rare 

l-septate,  3  per  cent,  16  x  3.1^  (only  one  measured) 
2-septate,  2  per  cent,  21  x  3.5/i  (only  one  measured) 
3  septate,  29  per  cent,  33  x  3.8  (22-41  x  3.3  4.2)m 
4-septate,  19  per  cent 
5-septate,  47  per  cent,  45  x  4.2  (36-64  x  4-4.4)  ^ 

Average  of  the  above  measurements: 
Conidia:     0-septate,  about  1  per  cent 
l-septate,  about  9  per  cent 
2-septate,  about  1  per  cent 
3-septate,  about  31  per  cent,  34.8  x  Z.l/x 
4-septate,  about  18  per  cent 
5-septate,  about  40  per  cent,  45  x  3.9 n 
6-septate,  very  exceptional,  45  x  4.5/x  (only  two  measured) 

Conidia  of  F.  truncatum  often  have  a  peculiar  flat  base,  and  this  species 
can  be  separated  from  all  the  other  Fusaria  of  potatoes  by  its  typically 
(though  not  always)  pomegranate  purple  to  carmine  conidial  masses. 

18.  Fusarium  lucidum  n.  sp.  (Figs.  Iv  and  15;  PI.  ii,  figs.  9  and  10; 
PL  IV,  fig.  12;  PI.  VI,  fig.  12) 

Conidia  typically  ellipsoid,  very  gradually  attenuate  toward  both  ends, 
distinctly  but  not  prominently  pedicellate,  5-septate,  54  x  4.05  (43-63 
x  3.7-4.7) M,  salmon,  often  of  very  bright  hues,  but  paler  or  denser  in  from 
small  to  large  (up  to  |  centimeter  in  diameter)  sporodochia;  no  chlamy- 
dospores;  conidiophores  typically  more  or  less  compound,  bushlike;  my- 
celium from  white  to  pale  cinnamon  and  pomegranate  near  substratum;, 
when  first  isolated  the  fungus  has  a  substratum,  on  potato  agar  without 
glucose  from  pale  pink  to  tints  of  pomegranate,  and  on  the  same  medium 
with  glucose  from  clay  to  buckthorn  lirown. 


158 


C.  D.  Sherbakoff 


Hab.     On  rotted  tubers  of  Solanum  tuberosum,  New  York  State. 

Differs  from  F.  effusum  mainly  by  absence  or  very  rare  occurrence  of 
6-  and  7-septate  conidia. 

Latin  description. — Conidiis  typice  ellipsoidalibus,  maxime  in  utrosque 
terminos  gradatim  attenuatis,  distincte  sed  non  insignite  pedicellatis, 
5-septatis,  54x4.05  (43-63  x  3.7-4.7) /x,  "salmon-color"  (R)  magnis,  in 
parvis  (usque  ad  |  cm.  diam.)  sporodochiis;  nullis  chlamydosporis;  co- 
nidiophoris  typice  plus  minusve  compositis,  fruticosis;  mycelio  ex  albo 
"pale  cinnamon"  (R)  vel  "pomegranate"  (R)  prope  substratum;  primum 


Fig.  15. —  Fusarium  lucidum.  a,  Sporodochial  conidia,  b,  conidiophores,  from  ^7-days-old 
culture  on  wheat  kernels;  c,  pseudopionnoial  conidia  from  11 -days-old  culture  on  slightly  acidified 
hard  potato  agar;  d,  sporodochial,  e,  aerial,  conidia  from  75-days-old  red  raspberry  cane  plug; 
T,  pseudopionnotal  conidia  from  36-days-old  culture  on  hard  oat  agar;  g,  sporodochial  conidia, 
H,  conidiophore,  from  20-days-old  culture  on  hard  lima-hean  agar  with  2  per  cent  glucose;  i,  pseudo- 
pionnotal conidia  from  7^ays-old  culture  on  hard  lima-hean  agar  with  2  per  cent  glucose; 
J,  sporodochial  conidia  from  65-days-old  ciiUure  on  potato  stem  plug;  k,  sporodochial  conidia 
from  24-days-old  culture  on  potato  tuber  plug;  l,  sporodochial  conidia  from  82-days-old  culture 
on  potato  tuber  plug  (the  two  at  the  left  abnormal) 

substrato,  in  agare  Solani  tuberosi  non  glucoso,  e  pallide  rubello  "  pome- 
granate" (R)  vel  simili  colore,  in  eodem  agare  glucoso,  ex  argillaceo 
"buckthorn-brown"  (R). 

Hab.     In  tuberibus  putridis  Solani  tuberosi.  New  York,  Amer.  bor. 

Measurements  of  conidia  from  cultures  on  different  media  are  as  fol- 
lows: 


FusARiA  OF  Potatoes  159 

On  hard  potato  agar,  slightly  acidified,  culture  eleven  days  old;  conidia 

from  pseudopionnotes : 

Conidia:     0-septate,  rare 

1-septate,  11  per  cent,  17  x  3.1  (12-22  x  2.9-3.5)/i 
2-septate,  7  per  cent,  28  x  3.8  (20-32  x  2.9-4.3) m 
3-septate,  68  per  cent,  43.7  x  3.8  (33-67  x  3^.4)^ 
4-septate,  4  per  cent,  55  x  4.2  (47-65  x  4-4.4) /x 
5-septate,  10  per  cent,  63  x  4.4  (57-72  x  4-4.8)  m 

On  red  raspberry  cane  plug,  culture  seventy-five  days  old;  conidia  from 

aerial  mycelium: 

Conidia:    0-septate,  rare 

1-septate,  1  per  cent 

3-septate,  5  per  cent,  43  x  3.8  (25^8  x  3.5^.4)  m 
4-septate,  14  per  cent,  45  x  3.8  (38-54  x  3-4.6)// 
5-septate,  80  per  cent,  51  x  4.2  (42-60  x  3.5-4.7) m 
6-septate,  rare 

On  potato  tuber  plugs,  culture  ninety-two  days  old;  conidia  from  a  m  :  - 
of  minute  sporodochia: 
Conidia:     0-septate,  rare 

1-septate,  3  per  cent 

2-septate,  2  per  cent 

3-septate,  25  per  cent,  31  x  3.8  (24-36  x  3-4.1)/i 

4-septate,  17  per  cent 

5-septate,  53  per  cent,  46  x  3.9  (36-58  x  3.5-4.7)  m 

6-septate,  rare,  55-60  x  3.8-4.7^  (only  a  few  measured) 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  seven  days  old; 
conidia  from  aerial  mycelium: 
Conidia:     0-septate,  40  per  cent 
1-septate,  35  per  cent 
2-septate,  5  per  cent 

3-septate,  14  per  cent,  41  x  4.2  (33-44  x  3.5^.8) /z 
4r-septate,  5  per  cent,  48  x  4.6  (42-53  x  4-5.3) m 
5-septate,    1    per    cent,  56x4.7  (53-58  x  4.3-4.9) ^   (only  ii . 
spores  measured,  the  largest  60  x  5.7/x) 


160  C  D.  Sherbakoff 

On  the  same  medium  as  above,  culture  twenty  days  old;  conidia  from  a 

small  sporodochium : 

Conidia:     3-septate,  1  per  cent 

4-septate,  12  per  cent,  44  x  4  (40-57  x  3.5-4.4)ju 
5-septate,  87  per  cent,  54  x  3.9  (40-68  x  3.5^.2) /x 

On  potato  tuber  plug,  culture  twenty-four  days  old;  conidia  from  aerial 

mycelium : 

Conidia:    3-septate,  10  per  cent,  46  x  SAfx.  (only  a  few  measured) 
4-septate,  30  per  cent,  47  x  3.5  (44-50  x  3-3.8) m 
5-septate,  60  per  cent,  51  x  3.7  (48-57  x  3.4-4.2) m 
6-septate,  rare,  60  x  4.2)u  (only  one  measured) 

On  potato  stem  plug,  culture  one  hundred  and  seven  days  old;  conidia 
from  a  sporodochial  mass  (much  deterioated) : 
Conidia:    3-septate,  15  per  cent 

4-septate,  5  per  cent 

5-septate,  80  per  cent,  56  x  3.8  (50-63  x  3.5^.2)^ 

On  steamed  whole  potato  tuoer,  culture  forty-nine  days  old;  conidia 
from  a  white,  semi-dry,  sporodochial  mass: 
Conidia:    3-septate,  50  per  cent,  36  x  3.9  (24^3  x  3.5^.1)/t 
4-septate,  35  per  cent 
5-septate,  15  per  cent,  43  x  4.1  (39-46  x  3.9-4.4) /x 

On  same  medium  as  above;   conidia  from  a  red   (old?)   sporodochial 

mass,  nearly  converging  into  semi-pionnotal  layer: 

Conidia:     0-septate,  very  rare 

3-septate,  8  per  cent,  46  x  3.7  (24-50  x  3-4)  m 
4-septate,  12  per  cent,  48  x  3.8  (41-52  x  3.5-4. l)/x 
5-septate,  80  per  cent,  54  x  4  (43-62  x  3.5-4.3) m 
6-septate,  very  rare,  about  57  x  4.2/i  (only  a  few  measured) 

On  medium  soft  potato  agar,  culture  fourteen  days  old;  conidia  from 
pseudopionnotes : 
Conidia:     3-septate,  28  per  cent,  42  x  3.6m  (only  four  measured) 

4-septate,  10  per  cent 

5-septate,  62  per  cent,  58  x  4  (43-65  x  3.5-4.7) m 


FusARiA  OF  Potatoes  161 

On  hard  lima-bean  agar,  culture  fourteen  days  old;  conidia  from  a  sheet 
of  small  sporodochial  masses  spread  over  the  substratum : 
Conidia:     3-septate,  3  per  cent,  41  x  3.2/i  (only  three  measured) 

4-septate,  1  per  cent 

5-septate,  96  per  cent,  60  x  3.8  (52-70  x  3.5-5)m 

On  wheat  grain  culture  fourteen  days  old;  conidia  from  small,  semi-dry 
sporodochia: 
Conidia:     1-septate,  rare 

3-septate,  14  per  cent 

4-septate,  26  per  cent 

5-septate,  60  per  cent,  56  x  3.7  (49-64  x  3.3-4.1)/x 

Average  of  the  above  measurements : 
Conidia:     0-septate,  about  3  per  cent 

1-septate,  about  4  per  cent,  17  x  3.1/i 
2-septate,  about  1  per  cent 
3-septate,  about  20  per  cent,  41  x  3.7/i 
4-septate,  about  14  per  cent 
5-septate,  about  58  per  cent,  54  x  4.05/i 
6-septate,  very  rare,  58  x  4.2m 

VI.  Section  ARTHROSPORIELLA  n.  sec. 

Microconidia  short  and  broad,  spindle-shaped,  0-  to  3-septate^i;  sporo- 
dochial macroconidia  when  present  sickle-shaped,  mostly  5-septate,  of 
Roseum  type;  pseudopionnotal  microconidia  mostly  5-  and  5-  to  7-, 
often  to  9-  and  more,  septate,  from  slightly  curved  to  straight  and  angui- 
form;  true  chlamydospores  absent;  aerial  mycelium  from  white  to  pale 
buff  and  different  hues  of  red  and  pink;  color  of  substratum  from  clay  to 
dfferent  hues  of  red. 

The  section  is  a  connecting  link  between  sections  Roseum  and  Sporotri- 
chiella  (through  F.  arthrosporioides) . 

19.  Fusarium  diversisporum  n.  sp.  (Fig.  16;  PI.  vii,  fig.  12) 
Conidia  varying  from  arthrosporial  (short,  spindle-shaped,  and  having 
an  average  measurement  when  3-septate  and  on  aerial  mycelium  of  28  x 

^1  These  conidia,  though  often  septate,  represent  an  abbreviated  type  and  thus  can  be  termed  micro- 
conidia. These  microconidia  are  often  referred  to  as  arthrosporial  because  of  their  resemblance  to  the 
conidia  of  the  genus  Arthrosporium. 


162 


C.  D.  Sherbakoff 


4.3/x)  to  sickle-shaped,  5-septate  type  dominant,  in  sporodochia  and 
pseudopionnotes,  measuring  48.5  x  3.63  (41-61  x  2.9-4.4) ^t;  in  pseudo- 
pionnotes,  6-  to  9-septate  conidia  are  common,  60-100  x  4.7-5.2/x,  from 
slightly  curved  to  straight  and  anguiform,  apically  pointed,  distinctly  but 
not  prominently  pedicellate,  in  mass  typically  of  light  pink-cinnamon 
color;  chlamydospores  absent;  sporodochia  when  present  often  of  a  large 
size  (up  to  3.7  centimeters  in  diameter);  aerial  mycelium  typically  well 
developed,  of  uniformly  medium  fineness,  white;  suljstratum,  on  potato 

h 


Fig.  16. —  Fusarium  diversisporum.  a,  Pseudopionnotal  conidia  from  26-days-old  culture 
on  hard  oat  agar;  b,  sporodochial  conidia,  c,  arthrosporial  conidia,  d,  aerial  conidiophores 
producing  arthrosporial  conidia,  from  76-days-old  culture  on  red  raspberry  cane  plug;  e,  pseudo- 
pionnotal conidia  from  8-days-old  culture  on  hard  lima-bean  agar  ivith  2  per  cent  glucose;  f,  typical 
sporodochial  conidia  from  11 3-day s-old  culture  on  potato  stem  plug;  G,  sickle-shaped,  normal 
conidia,  h,  arthrosporial,  more  or  less  abnormal,  conidia,  from  aerial  mycelium  of  45-days-old 
culture  on  whole  steamed  potato  tuber;  i,  pseudopionnotal  conidia,  3,  mycelial  conidiophores 
and  conidiophores  produced  directly  on  spores,  K,  conidia,  from  lO-days-.old  culture  on  medium 
potato  agar;  l,  typical  sporodochial  conidia  from  4('-days-old  culture  on  whole  steamed  potato 
tuber;  u,  chlamydospore-like  structures  in  old  conidia  from  173-days-old  culture  on  corn  agar; 
N,  sporodochial  conidia  from  4-^-days-old  culture  on  rye  straw;  o,  sporodochial  conidia  from 
116-days-old  culture  on  rye  straw;  v,  sporodochial  conidia  from  24-day  s-old  culture  on  potato 
tuber  plug;  q,  conidiophore  from  24-days-old  culture  on  potato  tuber  plug 


agar  rich  in  glucose,  ranging  from  onion-skin  pink  and  clay  color  when 
young  to  Saccardo's  amber  in  old  cultures. 

Hab.    On  rotted  tubers  of  Solanum  ttiberosum,  New  York  State,  in  close 
association  with  F.  metacroum. 


FusARiA  OF  Potatoes  163 

Latin  description. — Conidiis  ex  arthrosporialibus  (brevibus,  falci- 
formibus,  atque,  si  3-septata  et  in  aerio  mycelio,  plerumque  28  x  4.3m), 
falcifonnibus  plerumque  5-septatis,  48.5  x  3.63  (41-61  x  2.9-4.4)/i  in 
sporodochiis  pseudopionnotibusque;  in  pseudopionnotibus,  conidiis  6-9- 
septatis  frequentibus,  60-100  x  4.7-5.2^,  parum  curvatis  rectis,  demum 
anguiformibus,  apice  acutis,  distincte  sed  non  insignite  pedicellatis,  in 
totum  typice  pallide  "pinkish  cinnamon"  (R);  nuUis  chlamydosporis; 
sporodochiis,  si  exstant,  saepe  magnis  (usque  ad  3.7  cm.  diam.);  aerio 
myceUo  typice  plene  maturo,  uniformi  mediocri  subtilitate,  albo; 
substrato — in  Solani  tuberosi  agare  perglucoso — in  culturis  juvenibus, 
"onion-skin  pink"  (R)  vel  "clay-color"  (R),  in  culturis  maturis 
"Saccardo's  amber"  (R). 

Hab.  In  tuberibus  putridis  Solani  tuberosi  una  cum  F.  metacroo,  New 
York,  Amer.  bor. 

Measurements    of    conidia    from    cultures    on    different    media  are  as 

follows : 

On  slightly  acidified  hard  potato  agar,  culture  ten  days  old;  conidia 

from  thin  pseudopionnotes: 

Conidia:     0-septate,  rare 

1-septate,  7  per  cent,  10  x  2.4^ 

2-septate,  1  per  cent,  20  x  2.9/i 

3-septate,  36  per  cent,  36  x  3.1  (29-46  x  2.9-3.5)/x 

4-septate,  20  per  cent,  49  x  3.15  (40-53  x  3^)m 

5-septate,  35  per  cent,  60  x  3.8  (50-70  x  3.5^.2) m 

6-  to  9-septate,  1  per  cent  (60-100  x  4-5/x) 

On  red  raspberry  cane  plug,  culture  seventy-six  days  old;  conidia  from 
a  small  sporodochium : 
Conidia:     3-septate,  57  per  cent,  40  x  2.7(32^5  x  2.4-3) /x 

4-septate,  28  per  cent,  45  x  2.9(42-52  x  2.6-3.2)/i 

5-septate,  15  per  cent,  50  x  2.9(43-54  x  2.7-3.2)m 
On  hard  lima-bean  agar,  culture  eight  days  old;  conidia  from  a  thin 
layer  near  substratum: 
Conidia:     1-septate,  2  per  cent 

2-septate,  1  per  cent 

3-septate,  32  per  cent,  37  x  3.9  (28-43  x  3.5-5.3)^ 

4-septate,  9  per  cent 


164  C.  D.  Sherbakoff 

5-septate,  55  per  cent,  54  x  4.4  (40-61  x  3.5-5.5)  m 

6-septate  1  [61  x  4.9  (60-70  x  4.7-5.2) m  (only  four 

measured) 
7-septate  ^1    per  cent  -j  67  x  5  (60-79  x  4.7-5.2) ^   (only  four 

measured) 
8-septate  76  x  4.8  (70-79  x  4.7-4.8)  m  (only  three 

,  :;  ,;  J  [     measured) 

'On  potato  tuber  plug,  culture  twenty-four  days  old;  conidia  from  a 
Sporodochium,  many  spores  degenerated,  only  normal  ones  measured: 
Conidia:    0-septate,  none 

1-septate,  4  per  cent 

2-septate,  none 

3-septate,  50  per  cent,  32  x  3.1  (20-40  x  2.7-3.5)m 

4-septate,  22  per  cent 

5-septate,  24  per  cent,  42  x  3.5  (35-51  x  3-3.6) ai 

On  potato  stem  plug,  culture  one  hundred  and  thirteen  days  old;  conidia 

from  a  sporodochium: 

Conidia:  3-septate,  25  per  cent,  about  38  x  3.3m 
4-septate,  25  per  cent,  about  40  x  3.4/* 
5-septate,  50  per  cent,  42  x  3.5  (36-46  x  3-i.l)M 

On  whole  steamed  potato  tuber,  culture  forty-five  days  old: 

(1)  Conidia  from  aerial  mycelium 
Conidia:     A  —  Arthrosporial  type 

1-septate,  10  per  cent,  about  10  x  3.9/i 
2-septate,  3  per  cent,  16  x  4/* 
3-septate,  71  per  cent,  28  x  4.3  (19-37  x  4-5)m 
4-septate,  6  per  cent 

5-septate,  10  per  cent,  41  x  4.2  (37-46  x  4. 1-4.5)  ju 
B  —  Sickle-shaped  type 

0-septate,  6  per  cent,  about  10  x  2.6/* 
1-septate,  22  per  cent,  16  x  2.8  (13-19  x  2.4-3)m 
2-septate,  4  per  cent,  about  21  x  2.9ju 
3-septate,  40  per  cent,  30  x  3.1  (20-34  x  2.9-3.5)^ 
4-septate,  12  per  cent,  about  39  x  3.2/i 
5-septate,  16  per  cent,  45  x  3.3  (38-53  x  3-3.6)// 


FusARiA  OF  Potatoes  165 

(2)  Conidia  from  small  sporodochia  converging  into  a  nearly  continuous 
layer 
Conidia:     3-septate,  45  per  cent,  33  x  3.1  (20-41  x  2.5-3.5)m 

4-septate,  28  per  cent,  40  x  3.2^  (only  a  few  measured) 
5-septate,  27  per  cent,  43  x  3.3  (36-50  x  2.9-4.1)^ 

On  hard  lima-bean  agar,  culture  thirteen  days  old;  conidia  from  pseu- 
dopionnotal  stage: 
Conidia:     3-septate,  about  12  per  cent,  48  x  3^  (only  three  measured) 

4-septate,  about  8  per  cent 

5-septate,  80  per  cent,  61  x  3.3  (50-70  x  3.1-3.5) /x 

On  hard  oat  agar,  culture  thirty-seven  days  old;  conidia  from  aerial 
mycelium  close  to  substratum: 
Conidia:     1-septate,  1  per  cent 

3-septate,  20  per  cent,  31  x  3.3iU 

4-septate,  15  per  cent 

5-septate,-  60  per  cent,  45  x  3.7  (43-49  x  3.3-4) ^ 

6-septate,  4  per  cent,  61  x  4.2)li  (only  one  measured) 

On  same  medium  as  above,  culture  twenty-four  days  old;  conidia  from 
pseudopionnotes : 
Conidia:     3-septate,  10  per  cent,  28  x  3.3ju 

4-septate,  4  per  cent 

5-septate,  50  per  cent,  51  x  4)li 

6-septate,  30  per  cent,  60.6  x  4.2^ 

7-  and  8-septate,  6  per  cent,  75  x  43/1 

Average  of  the  above  measurements : 
Conidia:     0-septate,  about  0.5  per  cent,  10  x  3.25 /x 
1-septate,  about  4  per  cent,  12  x  3.0/i 
2-septate,  about  0.5  per  cent 
3-septate,  about  35.5  per  cent,  36  x  3.2/i 
4-septate,  about  15  per  cent 
5-septate,  about  44  per  cent,  48.5  x  3.63/i 
6-  to  9-septate,  about  0.5  per  cent,  60-100  x  4.7-5.2^ 

The  most  characteristic  features  of  the  fungus  are  as  follows:     0-  to 
3-septate,  spindle-shaped  conidia  of  aerial  mycelium;  3-  to  5-septate, 


166 


C.  D.  Sherbakoff 


very  narrow  sickle-shaped  conidia  of  sporodochia,  and  comparatively 
broad  and  longer  anguiforni;  6-  to  9-septate  conidia  of  pseudopionnotal 
stage  often  occurring  on  various  agars. 

20.  Fusarium  biforme  n.  sp.  (Figs,  lu  and  17;  PI.  vii,  fig.  10) 
Conidia  of  two  forms:  sporodochial  conidia  more  or  less  uniformly 
ellipsoid,  3-  to  5-septate,  3-septate  measuring  39  x  3.3  (36-46  x  2.9-3.6)/x, 
5-septate  measuring  51x3.5  (43-60  x  3-4) m;  pseudopionnotal  conidia  0- 
to  9-  and  even  up  to  12-septate,  sometimes  nearly  straight  or  anguiform, 
5-septate  measuring  52  x  4.2^,  6- to  9-septate  measuring  45-84  x  4-5. 8m; 
conidia  in  mass  typically  salmon-colored;  no  chlamydospores;  mycelium 

A 


nnxEo 


Fig.  17. —  Fusarium  b-tforme.  a,  Conidia  {sporodochium  3  jnillirneters  in  diameter),  b, 
CDiiidiophore,  from  29-daijs-old  culture  on  hard  oat  agar;  c,  conidia  from  aerial  mycelium  from 
7l-days-old  culture  on  potato  tuber  plug;  v>,  semi-pseudopionnotal  conidia  from  14-days-old 
c-dture  on  slightly  acidified  hard  potato  agar;  e,  conidiophores,  f,  typical  conidia,  g,  largest 
and  most  highly  septate  conidia,  from  10-day s-old  culture  on  rice 


well  developed,  uniform,  white  in  pseudopionnotal  stage  and  from  pink  to 
pomegranate  near  substratum  in  sporodochial  stage  (on  hard  oat  agar);^^ 
substratum  from  brick  red  to  pomegranate  (on  oat  and  other  agars). 

Hab.  On  rotted  tuber  of  Solatium  tuherosum,  together  with  F.  coer- 
uleum,  Wisconsin. 

Differs  from  F.  diversisporum  chiefly  in  color  of  mycelium  and  of  sub- 
stratum on  hard  oat  agar  and  other  agars,  and  in  absence  of  a  uniform 
and  typical  arthrosporial  stage  of  aerial  conidia,  although  single  conidia 
of  that  type  occur  here  also.  Differs  from  F.  diffusimi  by  the  presence  of 
8-  to  12-septate  conidia. 

*^  On  the  same  medium  F.  diversisporum  remains  from  white  to  clay  in  color. 


FusARiA  OF  Potatoes  167 

Jjatin  description. — Conidiis  biformibus:  conidiis  sporodochialibus,  plus 
minusve  aequabiliter  ellipsoidalibus,  3-5-septatis :  3-septatis,  39x3.3 
(36-46  x2.9-3.6)m;  5-septatis  51x3.5  (43-60  x  3-4)m;  conidiis  pseudo- 
pionnotalibus  0-9-septatis  vel  etiam  12-septatis,  interdum  prope  rectis 
vel  anguiformibus;  5-septatis,  52x4.2)u;  6-9-septatis,  45-84  x  4-5. 8^; 
conidiis  in  totum  typice  "salmon-color"  (R);  nullis  chlamydosporis; 
niycelio  plene  maturo,  uniformi,  albo  in  pseudopionnotum  gradu,  ex 
rubello  "pomegranate"  (R)  in  gradu  sporodochiali  (in  durae  avenae 
agare);  substrate  e  "brick  red"  (R)  "pomegranate"  (R)  (in  avenae 
agaribus  et  aliis  agaribus). 

Hab.  In  tuberibus  putridis  Solani  tuberosi  una  cum  F.  coeruleo,  Wis- 
consin, Amer.  bor. 

Measurements  of  the  conidia  on  different  media  are  as  follows : 

On  corn  agar,  culture  twenty-six  days  old;  conidia  from  a  thin  layer 
directly  on  substratum ; 

Conidia:     1-  to  4-septate,  20  per  cent  (about  an  equal  number  of  each) 
5-septate,  45  per  cent,  60  x  3.6  (50-70  x  3.4-3.8) m 

6-  to  9-septate,  35  per  cent,  80  x  4.4  (77-88  x  4. 1-4.7)  m 

On  hard  potato  agar,  slightly  acidified,  culture   fourteen  days  old;  co- 
nitlia  from  aerial  mycelium  close  to  substratum: 
Conidia:     0-septate,  0.5  per  cent,  12  x  3fx 

1-septate,  3  per  cent,  19  x  3^ 

2-septate,  rare,  25  x  3.2ix 

3-septate,  5  per  cent,  32  x  3.7  (24-51  x  3.5-4.2).^ 

4-septate,  2.5  per  cent 

5-septate,  80  per  cent,  51.5  x  4.3  (40-74  x  4-5.2) /x 

6-septate,  6  per  cent,  58  x  4.7  (50-75  x  4.3-5.3) /^ 

7-  and  8-septate,  3  per  cent,  68  x  4.7  (55-80  x  4.3-5.3) m 
9-  to  1 1-septate,  rare,  84  x  5.9/x  (only  a  few  measured) 

On  potato  tuber  plug,  culture  seventy-one  days  old;  conidia  from  aerial 
mycelium  close  to  substratum: 
Conidia:     0-septate,  2  per  cent,  9  x  3m 

1-septate,  6  per  cent,  14  x  3.3^,  a  few  15  x  5.7ai 

2-septate,  3  per  cent,  20  x  3.4^ 

3-septate,  30  per  cent,  27.5  x  3.9  (19-39  x  3.5-4.1)/x 

4-septate,  12  per  cent 


168  C.  D.  Sherbakoff 

5-septate,  44  per  cent,  43  x  4.1  (31-54  x  3.9-5.2)iu 

6-septate,  2  per  cent,  49  x  4.3  (45-72  x  4-4.9) m 

7-septate,  1  per  cent,  60  x  4.8  (59-73  x  4. 1-5.3)  m 

8-  and  9-septate,  rare,  60-78  x  4.5-5.8)u  (only  a  few  measured) 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  seven  days 
old;  conidia  from  aerial  mycelium: 
Conidia:     0-  and  1-septate,  79  per  cent 

3-septate,  15  per  cent,  36  x  4.6  (33-41  x  4.3-4.7)/i 

4-septate,  5  per  cent 

5-septate,  1  per  cent,  54  x  4.7  (53-66  x  4.3-5.3)  m 

On  hard  oat  agar,  culture  twenty-eight  days  old;  conidia  from  a  large 
(3  millimeters  in  diameter)  sporodochium : 
Conidia:     1-septate,  3  per  cent,  about  28  x  3  (28-37  x  2.3-3) )u 

2-septate,  1  per  cent 

3-septate,  45  per  cent,  39  x  3.3  (36-46  x  2.9-3.6) /x 

4-septate,  16  per  cent 

5-septate,  35  per  cent,  51  x  3.5  (43-60  x  3-4) m 

Average  of  the  above  measurements  for  all  non-sporodochial  conidia: 
Conidia:     0-septate,  about  9  per  cent,  11  x  3^ 

1-septate,  about  11  per  cent,  16.5  x  3.15/i 

2-septate,  about  2  per  cent 

3-septate,  about  20  per  cent,  32  x  4.1)u 

4-septate,  about  8  per  cent 

5-septate,  about  41  per  cent,  52  x  4.2/i 

6-  to  9-septate,  about  9  per  cent,  45-84  x  4-5. 8/i 

The  organism  when  first  isolated  had  large  sporodochia  (from  2  to  5 
millimeters  in  diameter),  and  the  substratum  and  mycelium  near  it  were 
from  rose  to  pomegranate  in  color;  later  the  color  of  mycelium  and  sub- 
stratum faded  and  no  sporodochia  were  produced  at  all;  during  the  last 
year  its  original  characters  —  both  color  and  sporodochia  —  reappeared. 
Under  just  what  influence  loss  of  characters  and  their  reappearance  took 
place  the  writer  is  unable  to  say,  although  it  seems  that  a  slightly  acidi- 
fied and  relatively  dry  medium  actually  helped  to  bring  the  fungus  to 
the  original  conditions. 


FusARiA  OF  Potatoes  169 

21.  Fusarium  anguioides  n.  sp.  (Figs.  It  and  18;  PL  vi,  fig.  11) 
Conidia  of  diverse  type,  ranging  from  arthrosporial  (short  spindle- 
shaped,  with  more  or  less  rounded  ends,  0-  to  3-septate)  to  typically 
slightly  curved  or  nearly  straight  and  anguiform,  1-  to  15-septate;  1- 
and  3-septate  conidia  typical  for  the  first  form  and  measuring  27  x  4.4 
(20-38  X  3.9-5. 3))u;  for  the  other  form  the  conidia  commonly  measuring 
as  follows: 

5-septate,  51  x  4.2  (47-68  x  3.9-4.6)  a* 

6-  and  7-septate,  76  x  4.6  (65-86  x  4.2-5.2)  m 

8-  and  9-septate,  89  x  4.86  (80-102  x  4.3-5.8) m 


Fig.  18. —  Fusarium  anguioides.  a,  Pseudopionnotal  conidia  from  6-days-old  culture  on 
slightly  acidified  hard  potato  agar;  b,  conidia  from  15-days-old  culture  on  ivheat  grain;  c,  conidio- 
phores  from  G-days-old  culture  on  slightly  acidified  hard  potato  agar;  d,  conidia  from  J^B-days- 
old  culture  on  wheat  grain;  e,  conidiophore  from  15-days-old  culture  on  wheat  grain;  f  and  a, 
conidiophores,  h,  conidia,  from  62-days-old  culture  on  red  raspberry  cane  plug;  i,  pseudopionnotal 
conidia  from  11 -days-old  culture  on  medium  potato  agar;  j,  conidiophores  from  62-days-old  culture 
on  red  raspberry  cane  plug;  k,  pseudopionnotal  conidia  from  13-days-old  hard  lima-bean  agar 


Color  of  conidia  in  pseudopionnotal  layer,  on  glucose  potato  agar,  ranging 
from  light  pinkish  cinnamon  to  cinnamon;  arthrosporial  conidia  of  com- 
mon occurrence  on  aerial  mycehum,  but  often  the  latter,  especially  on 
different  agar,  nearly  absent,  when  a  thin  spore  layer,  pseudopionnotes, 
is  produced  for  which  anguiform  conidia  are  typical. 

Hab.     On  rotted  tuber  of  Solarium  tuberosum  from  Castile,  New  York, 
in  association  with  F.  arcuosporum. 


170  C.  D.  Sherbakoff 

In  pseudopionnotal  stage  F.  anguioides  is  much  like  F.  biforme,  but 
has  no  sporodochial  stage,  or  rather  no  macroscopically  observable  spo- 
rodochia. 

Latin  description. — Conidiis  variis  typis,  interdum  arthrosporialibus 
(brevibus,  fusiformibus,  terminis  plus  minusve  rotundatis,  0-3-septatis) , 
interdum  typice  paulum  curvatis  vel  prope  rectis  anguiformibusque, 
1-15-septatis;  conidiis  primo  typo  typice  1-vel  3-septatis,  27x4.4 
(20-38  X  3.9-5. 3)/x;  conidiis  altero  typo:  5-septatis  plerumque  51x4.2 
(47-68  X  3.9-4.6) m;  6-7-septatis  plerumque  76x4.6  (65-86  x  4.2-5.2)iu; 
8-9-septatis  plerumque  89  x  4.86  (80-102  x  4.3-5.8) m-  Conidiis  in  strato 
pseudopionnotali,  in  agari  glucoso  Solani  tuberosi  e  pallide  "  pinkish- 
cinnamon"  (R)  "cinnamon"  (R);  saepe  conidiis  arthrosporialibus  in 
aerio  mycelio,  sed  hoc  mycelio  saepe  —  imprimis  in  alio  agari  —  prope 
absente,  quae  cum  ita  sint  tenues  sporarum  strati,  pseudopionnotes, 
oriuntur  cum  conidiis  typice  anguiformibus. 

Hab.  In  tuberibus  putridis  Solani  tuberosi,  una  cum  F.  arcuosporo, 
Castile,  New  York,  Amer.  bor. 

Measurements  of  conidia  on  different  media  are  as  follows: 

On  red  raspberry  cane  plug,  culture  sixty-two  days  old;  conidia  from 
aerial  mycelium  close  to  substratum: 
Conidia:     0-septate,  3  per  cent 

1-septate,  19  per  cent,  17  x  3  (12-22  x  2.5-4)  m 

2-septate,  9  per  cent 

3-septate,  43  per  cent,  30  x  3.5  (17-42  x  3-4.8) ^ 

4-septate,  7  per  cent 

5-septate,  18  per  cent,  47x4.2  (35-55  x  3-5.2)  m,  the  thickest 
50  X  5.9m 

6-septate,  1  per  cent 

7-septate,  rare,  the  longest  75  x  4.8/i 

On  hard  potato  agar,  culture  eleven  days  old ;  conidia  from  thin  pseudo- 
pionnotes : 

Conidia:     1-septate,  3  per  cent,  18  x  4.3/i  (only  a  few  measured) 
2-septate,  2  per  cent 
3-septate,  20  per  cent,  29x4.5  (20-35  x  4-6.5) m,  the  broadest 

34  X  6.5m 
4-septate,  10  per  cent 


FusARiA  OF  Potatoes  171 

5-septate,  44  per  cent,  52  x  4.6  (33-75  x  4. 1-6.2) /x 

^  I    f  9  per  cent<  72  x  5.2/i  (only  a  few  measured) 

8-septate  I  f  80  x  5.3 fx  (only  a  few  measured) 

9-septate  [  8  per  cent  -j  102  x  5.8^    (only  a  few  measured,  the 
I  [     largest  105  x  6.5m) 

11-septatel  f  91  x  5.8/i  (only  one  measured) 

12-septate/  \  101  x  5.7/i  (only  one  measured) 

On  hard  lima-bean  agar,  culture  thirteen  days  old;  conidia  from  thin 
pseudopionnotes : 

Conidia:     5-septate,    9  per  cent,  58  x  4.1  (53-62  x  3.9-1.4)^ 
6-septate,  12  per  cent,  78  x  4.3  (70-87  x  4. 1-4.5)  m 
7-septate,  19  per  cent,  86  x  4.3  (78-96  x  4. 1-4.5) /x 
8-septate,  32  per  cent,  93  x  4.4  (86-100  x  4.2-4.8) m 
9-septate,  17  per  cent,  94  x  4.4  (90-100  x  4.2-4.7) m 
10-septate,  7  per  cent,  94x4.4  (97-103  x  4.3-4.5) m  (only  four 

measured) 
11-septate,  2  per  cent,  108  x  4.4^  (only  one  measured) 
12-septate,  1  per  cent,  110  x  4.4^  (only  one  measured) 
13-septate,  1  per  cent,  126  x  4.8)u  (only  one  measured) 

On  wheat  grain,  culture  fifteen  days  old;  conidia  from  aerial  mycelium: 
Conidia:     0-septate,  very  rare 
1-septate,  very  rare 

2-septate,  very  rare,  26  x  3.1/i  (only  a  few  measured) 
3-septate,  5  per  cent 
4-septate,  2.5  per  cent 
5-septate,  89  per  cent,  60  x  4.2  (45-70  x  3.9-4.7)ai 

6-septate\  [^^  ""  ^'^  ^^^"^^  ""  4.1-4.4)m  (only  a  few 

7     \\    \  ^  PPr  cent  <      measured) 

[  85  X  4.3/i  (only  a  few  measured) 
„_  N  f  81  X  4.6m  (only  a  few  measured) 

f,  '      ,   ,     >0.5  per  cents  86  x  4.5m  (only  a  few  measured,  the 
9-septate/  |     longest  92  x  4.5^) 


172  C.  D.  Sherbakoff 

On  hard  lima-bean  agar,  culture  nine  days  old;  conidia  from  pseudo 

pionnotes : 

Conidia:     0-septate] 

1-septate  |>  1  per  cent 
2-septate  J 

3-septate,  2  per  cent,  45  x  4  (only  a  few  measured) 
5-septate,  40  per  cent,  63  x  4.3  (43-76  x  3.5-4.7) /x 
6-septate,  22  per  cent,  72  x  4.4  (62-79  x  4-4.7)  m 
7-septate,  18  per  cent,  80  x  4.5  (63-88  x  4.3-4.8) m 
8-septate,  10  per  cent,  87  x  4.7  (75-93  x  4.3-4.8) /x 
9-septate,  5  per  cent,  88  x  4.7/i  (only  two  measured) 
10-septate,  2  per  cent,  90  x  4.8m  (only  one  measured) 

On  wheat  grain,  culture  forty-six  days  old;  conidia  from  aerial  mycelium 
close  to  substratum: 

Conidia:     0-septate,  3  per  cent:  arthrosporial,  15  x  4.1  (10-22  x  3.9-4.4)/x; 
sickle-shaped,  20  x  2.8  (16-22  x  2.6-3.5) m 

1-septate,  27  percent!     ^  27x4.4     (20-38x3.9- 

2-septate,    4  per  cent  f      r  ox 

3-septate,  38  per  cent  j 

4-septate,  11  per  cent 

5-septate,  15  per  cent,  53  x  3.9  (42-62  x  3.5-4.2)m 

6-septate,  2  per  cent,  65  x  4.2  (54-70  x  3.9-5.2) /x 

7-  and  8-septate,  rare,  73-81  x  4. 1-4. 8m  (only  three  measured) 

Average  of  the  above  measurements: 
Conidia:     0-septate,  0.6  per  cent 
1-septate,  4.6  per  cent 
2-septate,  2.2  per  cent 
3-septate,  14  per  cent 
4-septate,  4  per  cent 
5-septate,  40  per  cent,  50  x  4.2m 
6-  and  7-septate,  16.8  per  cent,  76  x  4.6m 

8-  and  9-septate,  14.4  per  cent,  89  x  4.86m 

10-  to  15-septate,  3.4  per  cent,  103  x  4.9m  (the  largest  conidiura 
found  was  15-septate,  150  x  6m) 


FusARiA  OF  Potatoes 


173 


22.  Fusarium  anguioides  var.  caudatum  n.  var.  (Fig.  L9;  PL  vi,  fig.  9) 
Conidial  type  ver>'  much  the  same  as  that  of  F.  anguioides,  but  8- 
to  11-septate  conidia  very  rare  and  the  size  for  the  same  septation 
somewhat  larger;  conidia  never  in  macroscopically  observable  thick 
pseudopionnotes  as  is  often  the  case  in  F.  anguioides  when  grown  on  various 
agars.  Conidia  of  this  fungus,  even  in  comparatively  young  cultures, 
often  produce  on  one  end  a  long,  usually  unbranched,  germ  tube  (see 
certain  conidia  in  figure  19),  which  has  never  been  observed  in  F. 
anguioides. 


Fig.  19. —  Fusarium  anguioides  var.  caudatum.  a,  Pseiidopionnotal  conidia  from  10-days- 
old  culture  on  slightly  acidified  hard  -potato  agar;  b,  conidia  from  61 -days-old  culture  on  red 
raspberry  cane  plug;  c,  typical,  d,  degenerated,  conidia,  e,  conidiophores,  from  67-days-old  culture 
on  potato  stem  plug;  f,  conidia  froni  15 -days-old  culture  on  ivheat  grain;  g,  pseudopionnotal 
conidia  from  9-days-old  cidture  on  hard  lima-hean  agar;  h,  conidiophores,  i,  pseudopionnotal 
conidia,  j,  chlamydospore-like  mycelial  swelling,  k,  conidiophores,  from  11 -days-old  culture 
on  medium  potato  agar;  l,  pseudopionnotal  conidia  froyn  16-days-old  culture  on  hard  lima- 
hean  agar  with  2  per  cent  glucose;  M,  pseudopionnotal  conidia  from  37 -days-old  culture  on  hard 
oat  agar;  n,  conidiophores  from  11 -days-old  culture  on  medium  potato  agar 


Hab.     On  rotted  tubers  of  Solanum  tuherosum,   in  association   with 
F.  coeruleum,  Ithaca,  New  York. 

Measurements  of  conidia  from  cultures  on  different  media  are  as  follows: 


174  C.  D.  Sherbakoff 

On  red  raspberry  cane  plug,  culture  sixty-one  days  old: 
Conidia:     0-  and  1-septate,  10  per  cent 
2-  to  4-septate,  35  per  cent 

5-septate,  55  per  cent,  56  x  4.2  (35-80  x  3.7-4.8)At 
6-septate,  rare,  the  longest  85  x  5.2^ 

On  hard  lima-bean  agar,  culture  sixteen  days  old: 
Conidia:     0-septate,  17  per  cent,  13  x  2.7  (11-16  x  2.3-3.7) m 

1-septate,  18  per  cent,  22  x  3.3  (18-28  x  3^.4)  m,  the  broadest 

33  X  6.1/i 
2-septate,  12  per  cent 
3-septate,  40  per  cent,  38.5  x  4  (29-45  x  3.5-4.7)/x,  the  broadest 

33  X  6.1m 
4-septate,  3  per  cent 

5-septate,  7  per  cent,  60  x  4.5  (52-75  x  4. 1-5.4)  ^ 
6-septate,  3  per  cent,  67  x  5.2  (53-77  x  4.1-6.1)/* 
7-septate,  very  few,  82  x  5.2/x  (only  one  measured) 
8-septate,  few,  75  x  5.3  (72-88  x  5-5.6)  m  (only  two  measured) 
9-septate,  very  few,  94  x  5.2/i  (only  one  measured) 

On  hard  potato  agar,  culture  eleven  days  old : 
Conidia:     0-septate,  12  per  cent,  14  x  3.9  (8.7-20  x  2.6^.2) m 

1-septate,  11  per  cent,  17  x  A.lfx  (only  four  measured) 

2-septate,  9  per  cent 

3-septate,  47  per  cent,  40  x  4.3  (25-53  x  3.5-5.3) ^ 

4-septate,  8  per  cent 

5-septate,  12  per  cent,  66  x  4.6  (50-77  x  4-6.1)m 

6-septate,  \  /  79  x  5.3^  (only  one  measured) 


,   ,     (  I  per  cent  i  <-,,-,-  ^^    /     i  ix 

7-septate,  j  L^^  ^  ^•^'"  (only  one  measured) 

On  wheat  grain,  culture  fifteen  days  old: 
Conidia:    0-septate,  4  per  cent 

l-septate,  40  per  cent,  24  x  3.1  (15-27  x  2.7-3.6) m 

2-septate,  10  per  cent 

3-septate,  42  per  cent,  43  x  3.8  (36-62  x  3.5-5.2)// 

4-septate,  2  per  cent 

5-septate,  2  per  cent,  55  x  4.1  (43-62  x  4^  5)/i 

6-septate,  few,  57  x  4.3/t  (only  one  measured) 

7-septate,  very  few,  79  x  4.3/t  (only  one  measured) 


FusARiA  OF  Potatoes  175 

■  On  hard  lima-bean  agar,  culture  nine  days  old: 
Conidia:     0-septate,  14  per  cent 
1-septate,  28  per  cent 
2-septate,  5  per  cent 
3-septate,  32  per  cent,  44  x  3.6  (29-63  x  S-4)n  (exceptionally 

4.8/x  in  diameter) 
4-septate,  5  per  cent 
5-septate,  16  per  cent,  65  x  3.9  (52-79  x  3.5-4.8) m 

Average  of  the  above  measurements : 
Conidia:     0-septate,  about  10.4  per  cent,  13.5  x  3.3)U 
1-septate,  about  20.4  per  cent,  21  x  3.5)Lt 
2-septate,  about  9.2  per  cent 
3-septate,  about  35.2  per  cent,  41  x  3.9/i 
4-septate,  about  5.6  per  cent 
5-septate,  about  18.4  per  cent,  60.4  x  4.26^ 
6-  and  7-septate,  about  0.8  per  cent,  82  x  4.9/u 
8-  and  9-septate,  very  rare,  85  x  5.2/x 

23.  Fusarium  arthrosporioides  n.  sp.  (Figs.  1,  l  to  p,  and  20;  PI.  iii, 
figs.  3  and  4;  PI.  vii,  fig.  11) 

Conidia  of  three  types:  (1)  elliptical,  apically  attenuate,  slightly 
pedicellate,  mostly  5-septate,  48x4.3  (45-55x4-4.7)//;  (2)  arthrosporial, 
0-  to  3-(5-)  septate,  broad  spindle-shaped,  3-septate  measuring  about 
25x5.4  (19-33  x  4.7-6) m;  (3)  sporotrichial,  mostly  0-septate,  4.5x3.8 
(2.9-9  X  2.6-8)  At.  Type  1  is  found  mostly  in  pseudopionnotes,  type  2  on 
aerial  mycelium,  and  type  3  mainly  in  small,  dense,  bushlike  clusters  of 
conidiophores,  often  resembling  sporodochia;  no  true  chlamydospores; 
aerial  mycelium  from  white  to  light  tints  of  rose  and  salmon  hues,  uniform  or 
covered  with  knotted,  more  or  less  large,  areas;  substratum  from  clay 
color  to  buckthorn  brown  and  bright  red  (Plate  iii,  fig.  4).  The  organism 
occupies  an  intermediate  position  between  sections  Arthrosporiella  and 
Sporotrichiella. 

Hab.     In  discolored  tissues  of  tuber  of  Solanum  tuberosum,  Ireland. 

The  organism  remained  for  a  long  time  in  pure  culture,  with  well- 
developed  aerial  mycelium  and  with  a  bright  red  color  (Plate  iii,  fig.  4); 
the  dominant  type  of  conidia  was  sickle-shaped,  5-septate.  During  the 
last  year  —  the  second  year  of  its  cultivation  —  the  development  of  aerial 
mycelium  has  become  poorer,  the  color  of  the  substratum  has  changed  to 


176 


C.  D.  Sherbakoff 


clay  color  and  buckthorn  brown,  and  sporotrichic  conidia  are  the  com- 
monest type.  Whether  the  organism  has  changed  only  temporarily  or 
not  is  as  yet  unknown."*^ 

Latin  descri'ption. — Conidiis  tribus  typis:    (1)  conidiis  ellipticis,    apice 
attenuatis,  paulum  pedicellatis,  plerumque  5-septatis,  48  x  4.3   (45-55  x 


-Fig.  20. —  Fusarium  arthrosporioides.  a,  Normal  pseudopionnolal  conidia,  B,  arthrosporiah 
conidia,  from  14-days-old  culture  on  hard  lirna-bean  agar;  c,  sporodochial  conidia  from  64- 
days-old  culture  on  hard  lima-bean  agar  with  2  per  cent  glucose;  d,  arthrosporial,  e,  normal, 
conidia,  r,  conidiophores,  from  11-days-ald  culture  on  medium  potato  agar;  g,  aerial  conidia, 
H,  conidiophores,  from  11-days-old  culture  on  slightly  acidified  hard  potato  agar;  i,  conidia 
and  chlamydospores  from  76-days-old  culture  on  red  raspberry  cane  plug;  J,  conidiophores  from 
11-days-old  cidture  on  medium  potato  agar;  k,  normal,  i.,  arthrosporial,  type  of  conidia,  m,  conidio- 
phores, from  aerial  mycelium  of  16-days-old  culture  on  hard  lima-bean  agar  with  2  per  cent 
glucose;  n,  sickle-shaped  conidia,  o,  arthrosporial  and  sporotrichial  conidia  and  conidiophore 
of  the  sporodochial  stage,  from  36-days-old  culture  on  rye  grain;  p,  chlamydospores 


4-4.7)iu;  (2)  conidiis  arthrosporialibus,  0-3(5)-septatis,  latis  fusifor- 
mibus,  3-septatis  circa  25x5.4  (19-33  x  4. 7-6)^;  (3)  conidiis  sporotri- 
chialibus,  plermnque  0-septatis,  4.5  x  3.8  (2.9-9  x  2.6-8)  ai.  Typo  primo 
plerumque  in  pseudopionnotibus,  typo  altero  in  aerio  mycelio,  typo  tertio 
plerumque  in  parvis  densis  fruticosis  conidiophoris  uveosis,  saepe  similibus 
sporodochiis;  nullis  veris  chlamydosporis;  aerio  mycelio  ex  albo  pallide 
roseo  "  salmon  color  "  (R),  uniformi  vel  nodosas  plus  minusve  magnas  areas 

«  In  this  connection  see  last  paracraph  in  description  of  F.  biforme  (page  168). 


FusARiA  OF  Potatoes 


177 


exhibente;  substrate  ex  argillaceo  "  buckthorn  brown"  (R)  vel  nitide  rubro 
(Tab.  Ill,  fig.  4).  Fungo  locum  medium  inter  Sectiones  Arthrosporiellam 
et  Sporotrichiellam  obtinente. 

Hab.     In  textibus  decoloratis  Solani  tuberosi  tuberum,  Hibernia. 

Measurements  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  eleven  days  old;  conidia 
from  aerial  mycelium: 
Conidia:     0-septate,  0.5  per  cent,  12  x  2.7/i 

1-septate,  15.5  per  cent,  25  x  3.8  (17-30  x  2.6^.7))u 
2-septate,  3  per  cent,  27  x  -in 
3-septate,  77.5  per  cent,  35  x  3.5  (22-48  x  3-4.4) m 
4-septate,  3  per  cent,  43  x  4.2  (35-50  x  3.5-4.8) /x 
5-septate,  0.5  per  cent,  47  x  4.4m  (only  a  few  measured) 
On  hard  lima-bean  agar  with  2  percent  glucose,  culture  sixteen  days  old: 
'  0-septate,  4.7  per  cent,  10  x  2.6m  (only  a  few 
measured) 
1-septate,    4.7    per    cent,   19x3.1    (14-24  x 

2.9-3.5)  M 
2-septate,  few,  28  x  3.3m  (only  a  few  measured) 
3-septate,  5.9  per  cent,  34  x  4  (31-40  x  3.3- 

4.7)m 
4-septate,    0.5 
4.1-4.7)m 
5-septate,    0.6 
4.1-4.8)m 
0-septate,  13  per  cent,  8.5  x  4.3  (6-12  x  3.5- 

6.4)m 
1-septate,    23.5    per    cent,    15x4.4   (9-20  x 

3.5-5.3)m 
2-septate,    11.7    per    cent,   18x5.2  (13-35  x 
4.7-6)  M 


(1)  Sickle-shaped  conidia 


per    cent,    43x4.3    (35-44  x 
per    cent,    47x4.4    (43-54  x 


(2)  Arthrosporial  conidia 


3-septate,    35.4  per    cent,   25x5.4   (19-33  x 

4.7-6)  M 
4-septate,  few,  39  x  6  (33-47  x  5-7) m 
5-septate,  few,  46  x  5.7  (42-56  x  5.2-6) m 
The    largest    conidium    observed    was   8- 

septate  (exceptionally  close-septate),  and 

measured  58  x  6.5m 


178  C.  D.  Sherbakoff 

On  potato  stem  plug,  culture  one  hundred  and  seven  days  old: 
Conidia:     1-septate,  52  per  cent,  about  13  x  3.5/x 
2-septate,  7  per  cent 
3-septate,  31  per  cent,  34  x  3.4/x 
4-septate,  3  per  cent,  43  x  3.6ai 
5-septate,  7  per  cent,  45  x  4  (40-50  x  3.4-4.3) m 

On  hard  lima-bean  agar,  culture  sixty-four  days  old;  conidia  from  a 

sporodochium : 

Conidia:     1-septate,  1  per  cent 

3-septate,  12  per  cent,  26  x  3.4  (22^4  x  3-3.6) m 
4-septate,  5  per  cent,  43  x  3.9/x  (only  two  measured) 
5-septate,  81  per  cent,  48x4  (43-52  x  3.5-4.3) m 
6-septate,  1  per  cent,  about  50  x  4.1/z  (only  two  measured) 

On  hard  lima-bean  agar,  culture  fourteen  days  old ;  conidia  from  a  dense 

mycelial  growth  at  the  bottom  of  the  slant: 

Conidia:     0-septate,  1.5  per  cent,  13  x  4.8/i  (only  three  measured) 
1-septate,  10  per  cent,  20  x  5.2  (9-27  x  4.1-7)  m 
2-septate,  4.  per  cent,  22  x  8.3ju  (only  three  measured) 
3-septate,  38  per  cent,  28x5.2  (19-39  x  4.3-5.9) m 
4-septate,  4  per  cent 

5-septate,  37  per  cent,  55  x  4.7  (43-70  x  4.4-5.3)ju 
6-septate,  4  per  cent,  61  x  5  (54-70  x  4.8-5.3)/! 
7-septate,  1.5  per  cent,  69x5  (64-79  x  4. 7-5.3) /z 

On  rye  grain,  culture  thirty-six  days  old;  conidia  from  a  sporodochium, 
of  sporotrichial  type: 
Conidia:     0-septate,  97  per  cent,  4.5  x  3.8  (2.9-9  x  2.6-8) m 

1-septate,  3  per  cent,  10.2  x  5.6  (8.5-14  x  4.2-6.3)  m 

2-septate,  rare 

3-septate,  rare 

Average  of  the  above  measurements: 
^     .  ,.        ^        ,    ,      ,_  ,  J  4.5  x  3.8 u  (sporotrichial  form) 

Coniia:    0-septate,  17  per  centj  j^.i  ^  3.8^  (arthrosporM  form) 

1-septate,  18  per  cent,  17  x  14.2/i 

2-septate,  6  per  cent 

3-septate,  33  per  cent,  25  x  5.4/i  (arthrosporial  form) 


FusARiA  OF  Potatoes 


179 


4-septate,  3  per  cent 

5-septate,  21  per  cent,  48  x  4.3/x  (sickle-shaped) 
6-septate,  1  per  cent,  55.5  x  4.55^  (sickle-shaped) 
7-septate,  0.5  per  cent,  69  x  5/x  (sickle-shaped) 

In  the  case  of  this  organism,  the  average  percentage  of  septation  of 
conidia  is  of  no  value  because  of  the  great  diversity  of  the  forms  occurring. 
Therefore  it  is  a  safer  basis  to  consider  each  stage  (sporodochial  and  from 
aerial  mycelium)  by  itself  separately. 


Fig.  21. —  Fusarium  arthrosporioides  var.  asporotrichius.  a,  Aerial  conidia  from  7-days-old 
culture  on  hard  lima-bean  agar  with  2  per  cent  glucose;  b,  sporodochial  conidia  from  82-daxjs- 
old  culture  on  potato  tuber  plug:  c,  d,  conidiophores,  from  11 -days-old  culture  on  slightly  acidified 
hard  potato  agar;  e,  aerial  conidia  from  25-days-old  cidture  on  potato  tuber  plug;  f  and  g,  conidio- 
phores, H,  pseudopionnotal  conidia,  from  11 -days-old  culture  on  slightly  acidified  hard  potato 
agar;  i,  conidia  from  68-days-old  culture  on  red  raspberry  cane  plug;  J,  arthrosporium-like, 
K,  normal,  conidia  from  aerial  mycelium  from  14-days-old  cidture  on  hard  lima-bean  agar; 
L,  aerial  conidia  from  36-days-old  cidture  on  rye  grain;  u,  sporodochial  conidia  from  14-days- 
old  culture  on  hard  lima-bean  agar 


24.  Fusarium  arthrosporioides  var.  asporotrichius  n.  var.  (Figs.  1,r  and 
s,  and  21 ;  PI.  vii,  fig.  9) 

This  fungus  is  very  much  the  same  as  F.  arthrosporioides,  but  differs 
from  the  latter  by  typical  absence  of  sporotrichial  sporodochia  and  by 
more  pronounced  and  common  production  of  from  medium  to  large 
(up  to  3  millimeters  in  diameter)  sporodochia  with  sickle-shaped,  5-sep- 
tate conidia,  51.2x4.3  (46-59  x  4. 15^.7)  m,  as  dominant  type. 


180  C.  D.  Sherbakoff 

Hab.     On   rotted   tubers   of   Solanum   tuberosum   in   association   with 
F.  Solani  and  F.  coeruleum,  New  York  State. 
Measurements  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  eleven  days  old,  conidia 

from  pseudopionnotes : 

Conidia:     0-septate,  0.8  per  cent 

1-septate,  3.4  per  cent,  20  x  3.3/x 

2-septate,  2.5  per  cent,  30  x  3.8m 

3-septate,  49  per  cent,  40  x  4  (30-56  x  3-4.7) /x 

4-septate,  21.8  per  cent,  50  x  4.3  (43-60  x  3.9-4.5) /x 

5-septate,  22.5  per  cent,  53.5  x  4.4  (49-62  x  4-4.7) m 

On  red  raspberry  cane  plug,  culture  sixty-eight  days  old;  conidia  from 

a  sporodochium : 

Conidia:  1-septate,  very  rare 
2-septate,  very  rare 

3-septate,  9  per  cent,  41  x  3.7  (21^8  x  3.3-4.4) m 
4-septate,  24  per  cent,  46  x  4.1  (36-60  x  3.8-4.7)^ 
5-septate,  67  per  cent,  51  x  4.2  (42-62  x  3.9-4.7) m 
6-septate,  rare,  62-70  x  4.1-4.8/x  (only  a  few  measured) 

On  potato  tuber  plug,   culture  eighty-two  days  old;  conidia  from  a 
sporodochium : 
Conidia:     1-septate,  rare 

2-septate,  rare 

3-septate,  6  per  cent,  36  x  3.8  (25-42  x  3.5^.1)ai 

4-septate,  17  per  cent 

5-septate,  77  per  cent,  49  x  4.2  (43-55  x  3.5-4.7)^ 

On  hard  lima-bean  agar,  culture  seven  days  old;  conidia  from  aerial 
mycelium : 

Conidia:  0-septate,  3  per  cent 
1-septate,  8  per  cent 
2-septate,  8  per  cent 
3-septate,  65  per  cent,  39x4.1  (31-67x3.9-5.7)/!,  the  longest 

68  X  4.4m 
4-septate,  14  per  cent,  49  x  4.7  (44-60  x  4.2-5.3) m 
5-septate,  2  per  cent,  59  x  4.8  (52-63  x  4.3-5.7)/i 


FusARiA  OF  Potatoes  181 

On  potato  tuber  plug,  culture  twenty-five  days  old;  conidia  from  aerial 

mycelium : 

Conidia:     0-septate,  rare,  about  16  x  2.5m 

1-septate,  7  per  cent,  22  x  3.7^  (only  three  measured) 
2-septate,  6  per  cent,  27  x  4.1^  (only  three  measured) 
3-septate,  40  per  cent,  35  x  4.3  (29-45  x  3.8-4.8) m 
4-septate,  28  per  cent,  43  x  4.7  (35  x  49  x  4.1-5.2)^,  the  broadest 

51  X  5.9m 
5-septate,  19  per  cent,  45  x  4.7  (40-53  x  4.3-4.9)m 
6-septate,  only  one  observed,  78  x  5.2m 

On  whole  steamed  potato  tuber,  culture  forty-six  days  old: 

(1)  Conidia  from  a  medium  large  (2  millimeters  in  diameter)  sporo- 
dochium 

Conidia:     1-septate,  2.5  per  cent,  about  16  x  3m 

2-septate,  2.5  per  cent,  about  28  x  3.5  (20-40  x  3.3-3.8jm 
3-septate,  31  per  cent,  38.5  x  3.7  (19^4  x  3^.1)m 
4-septate,  34  per  cent,  45  x  4m  (only  three  measured) 
5-septate,  30  per  cent,  48  x  4.15  (44-53  x  3.9-4.7)m 
6-septate,  very  rare,  61  x  4.3m  (only  one  measured) 

(2)  Conidia  from  a  small  sporodochium 
Conidia:     1-septate,  2  per  cent 

2-septate,  rare 

3-septate,  51  per  cent,  40  x  3.9  (35-43  x  3-4.1)m 
4-septate,  24  per  cent,  42  x  4.1.  (36-50  x  3.5-4.8)m 
5-septate,  23  per  cent,  46  x  4.2  (42-50  x  4-4.5) m 

On    medium    potato    agar,    culture    eleven    days    old;    conidia    from 
pseudopionnotes : 

Conidia:     3-septate,  13  p3r  cent,  39  x  4.3  (28-48  x  3.5-4.8)m 
4-septate,  8  per  cent 
5-septate,  79  per  cent,  48  x  4.6  (41-61  x  3.8-4.9)m 

On  hard  lima-bean  agar,  culture  fourteen  days  old: 
(1)  Conidia  from  aerial  mycelium 
Conidia:     0-septate,  6  per  cent,  11  x  4.6  (6-18  x  4-5.3) m 

1-septate,  13  per  cent,  18  x  5  (10-25  x  4.1-5.5)m 


182  CD.  Sherbakoff 

2-septate,  10  per  cent,  24x5.1  (20-30  x  4.3-5.5) m  (only  three 

measured) 
3-septate,  39  per  cent,  31  x  5.2  (22-43  x  4.1-6.2)m 
4-septate,  7  per  cent 

5-septate,  25  per  cent,  56  x  4.7  (42-70  x  4-5.9) m 
6-septate,  very  few,  63  x  4.9ju  (only  one  measured) 

(2)  Conidia  from  a  sporodochium 
Conidia:     3-septate,  about  5  per  cent,  36  x  3.1m  (only  a  few  measured) 
4-septate,  about  5  per  cent 
5-septate,  about  90  per  cent,  58  x  4  (52-65  x  3.5-4.8) /x 

On  rye  grain,  culture  thirty-six  days  old: 
Conidia:     0-septate,  3  per  cent 
1-septate,  6  per  cent 
2-septate,  2  per  cent 

3-septate,  55  per  cent,  38  x  3.4  (27-50  x  3-4.4) /x 
4-septate,  20  per  cent 
5-septate,  14  per  cent,  50  x  3.6  (43-60  x  3. 1-4.4) ^ 

Average  of  the  above  measurements: 
Conidia:     0-septate,  1  per  cent 
1-septate,  3  per  cent 
2-septate,  3  per  cent 
3-septate,  33  per  cent 
4-septate,  19  per  cent 
5-septate,  41  per  cent,  51.2  x  4.3/i 
6-septate,  very  rare 

25.  Fusarium  diplosporurn  Cke.  et  Ell. 

Cf.  Cooke,  M.  C,  and  Ellis,  J.  B.,  Grevillea  7:38.  1878.  Saccardo, 
Syll.  Fung.  4:701.    1886. 

The  following  description  is  from  Saccardo: 

"  Roseum,  pulvinatum;  conidiis  aliis  fusiformibus,  utrinque  acutis, 
arcuatis,  nucleatis,  demum  leniter  3-septatis  40 )U  long.,  aliis  ellipticis, 
uniseptatis  18  x  8;u. 

"  Hab.     In  caulibus  Solani  tuberosi,  New  Jersey,  Amer.  bor." 

The  abbreviated,  arthrosporial,  uniseptate,  conidia,  18  x  8ju  in  size, 
are  so  uncommon  that  there  is  no  doubt  in  the  writer's  mind  that  the 


FusARiA  OF  Potatoes  183 

organism  could  easily  be  identified  when  found,  and  thus  must  be  recog- 
nized as  a  good  species.     The  organism  was  not  isolated  by  the  writer. 

VII.  Section  Sporotrichiella  Wr.  (Fig.  1q).  Wollenweber,  H.  W., 
Maine  Agr.  Exp.  Sta.,  Bui.  219:256.    1913 

Fusaria  of  this  section  have  from  pyriform  to  nearly  globular,  mostly 
0-septate,  microconidia.  Typical  sickle-shaped,  septate  conidia  always 
present,  at  least  in  young  artificial  cultures. 

Only  one  species  of  this  section  is  presented  here.  This  species  was 
twice  isolated  from  rotted  potato  tubers,  and  thus,  at  least  in  a  way,  may 
be  considered  as  of  more  or  less  common  occurrence  on  this  substratum. 
There  are  many  other  Fusaria  of  this  section  reported  on  such  substrata 
as  corn,  carnations,  apples,  and  others,  a  number  of  which  are  discussed 
by  Lewis  (1913).  None  of  the  species  of  this  section  mentioned  by  him, 
however,  seem  to  be  identical  with  the  one  here  reported. 

Lewis  (1913:257)  reports  that  the  following  organisms  were  isolated 
also  from  potatoes:  (1)  F.  Poae  (Peck)  Wr.,  (2)  F.  Solani  (Mart.)  Ap.  et 
Wr.,  (3)  F.  conglutinans  Wr.,  (4)  F.  Helianthi  Sacc.  var.,  (5)  F.  qnrinuni 
(Fries)  Sacc,  and  (6)  F.  orthoceras  Ap.  et  Wr. 

Numbers  2  and  6  are  described  in  this  paper;  numbers  1  and  4  are  closely 
related  to  F.  sporotrichioides  n.  sp.,  and  belong  to  section  Sporotrichiella; 
number  3  belongs  to  section  Elegans  and  differs  from  F.  orthoceras  by 
absence  of  red- wine  color  on  rice  (see  Wollenweber,  1913  a: 30);  number 
5  may  belong  to  section  Arthrosporiella. 

No  technical  description,  except  results  of  inoculations  —  for  potatoes 
always  negative  —  and  certain  characters  of  color  and  of  colony  growth, 
is  given,  and  thus  a  proper  identification  is  rendered  impracticable. 

26.  Fusarium  sporotrichioides  n.  sp.  (Figs.  1q  and  22;  PI.  iii,  fig.  1) 
Conidia  scattered  in  aerial  mycelium  or  in  pseudopionnotes  and  distinct 
sporodochia;  of  diverse  type,  ranging  from  unicellular,  more  or  less  pyri- 
form, microconidia  of  sporotrichial  form,  to  sickle-shaped,  3-  to  10- 
septate,  apically  pointed,  pedicellate,  macroconidia;  0-septate,  sporo- 
trichial conidia  average  10.5x6  (9.5-11.4  x  5. 6-6.5) /x;  sickle-shaped, 
3-septate  conidia  average  30.4  x  3. 8/^,  and  5-septate  average  50.5x4.3/x; 
conidia  of  pseudopionnotes  stage  resemble  those  of  F.  anguioides; 
chlamydospores  often  present,  intercalary,  commonly  in  small  clusters; 


184 


C.  D.  Sherbakoff 


color  of  aerial  mycelium  and  of  substratum  from  white  to  clay  (PL  iii, 
fig.  1)  and  pink,  similar  to  the  color  of  F.  bullatum  var.  roseum  (PI.  iii, 
fig.  2). 

Hab.  On  rotted  tubers  of  Solarium  tuberosum,  together  with  F.  Solani 
and  F.  oxysporum,  New  York  State. 

Latin  description. — Conidiis  in  aerio  mycelio  sparsis  vel  in  pseudopion- 
notibus  et  sporodochiis  distinctis;  typis  variis:  interdum  microconidiis 
unicellularibus,   plus  minusve  pyriformibus,   sporotrichialibus;  interdum 


I  Fig.  22. —  Fusarium  sporotrichioides.  a,  Pseudopionnotal  conidia,  b,  various  simple  conidio- 
phores,  c,  balls  of  conidia,  d,  germinating  conidium,  from  5-days-old  culture  on  hard  potato 
agar;  E,  sporodochial  conidia,  f,  chlamydospores,  g,  hall  of  conidia,  h,  compound  conidiophores, 
from  86-days-old  culture  on  hard  potato  agar;  i,  sporotrichial  conidia  {some  germinating), 
J,  conidiophores,  from  atrial  mycelium  of  1 6-day s-old  culture  on  wheat  grain;  k,  typical,  thick- 
walled  sporotrichial  conidia,  l,  sickle-shaped  conidia,  m,  conidiophores  producing  sickle-shaped 
conidia,  n,  conidiophore  producing  sporotrichial  conidia,  o,  plectenchyniic  stroma,  from  52- 
days-old  culture  on  red  raspberry  cane  plug 


macroconidiis  falciformibus,  3-10-septatis,  apice  acutis,  pedicellatis; 
conidiis  0-septatis  sporotrichialibus  plerumque  10.5x6  (9.5-11.4x5.6- 
6.5)jLi;  falciformibus,  3-septatis  30.4  x  3. 8^,  et  5-septatis  50.5x4.3/x; 
conidiis  pseudopionnotum  gradu  similibus  conidiis  F.  anguioidum;  chlamy- 
dosporis  saepe  visis,  intercalaribus,  plerumque  minutis  uveosis;  aerio 
mycelio  substratoque  ex  albo  argillaceo  vel  rubello,  simili  colore  F.  bullati 


FusARiA  OF  Potatoes       '  185 

Hab.     In  tuberibus  putridis  Solani  tuberosi  una  cum  F.  Solani  et  F. 
oxysporo,  New  York,  Amer.  bor. 

Measurements  of  conidia  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  five  days  old;  conidia 
from  pseudopionnotes : 
Conidia:     0-septate,  2  per  cent 

1-septate,  10.5  per  cent,  19  x  3.5At 

2-septate,  5.5  per  cent,  28  x  3.7/x 

3-septate,  37  per  cent,  32.5  x  4.2  (24-50  x  3.9-4.7)^ 

4-septate,  6  per  cent,  45  x  4.2/i 

5-septate,  33  per  cent,  48x4.5  (40-62  x  3.9-5.3) m 

6-  to  10-septate,  6  per  cent,  50-90  x  5-6. Iju 

On  hard  potato  agar,  culture  eighty-six  days  old;  conidia  from  a  small 
sporodochium,  semi-dry: 
Conidia:     3-septate,  nearly  100  per  cent,  29.5  x  3.4  (20-41  x  3-4) m 

On  red  raspberry  cane  plug,  culture  fifty-two  days  old: 

(1)  Conidia  of  sporotrichial  form 

Conidia:     0-septate,  97  per  cent,  9.5  x  6.5  (7-12  x  4-7.5) m 
1-septate,  3  per  cent,  13.5x5.2  (10-15  x  4.8-6) m 
2-septate,  rare 
3-septate,  exceptional,  one  measured,  21  x  5.2/i 

(2)  Conidia  of  sickle-shaped  form 

Conidia:     0-septate,  35  per  cent,  11  x  2.9  (10-13  x  2.5-3.1)m 
,  1-septate,  60  per  cent,  15.5  x  3.2  (12-22  x  2.9-3.5)m 
2-septate,  very  rare 
3-septate,  5  per  cent,  25  x  3.5  (20-28  x  3-4)^1 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  10  days  old; 

conidia  from  a  pseudopionnotes: 

Conidia:  0-septate,  5  per  cent,  10  x  3  (5.2-16  x  2.1-3.7)m 
1-septate,  15  per  cent,  22  x  3.3  (16-28  x  3-3.5)m 
2-septate,  2  per  cent 

3-septate,  22  per  cent,  33  x  3.8  (27^9  x  3.5-4.8) /x 
4-septate,  23  per  cent,  45  x  4  (38-49  x  3.9-4. 1)^ 
5-septate,  30  per  cent,  51  x  4.1  (41-62  x  3.5-4.7) /x 


186  C.  D.  Sherbakoff 

6-septate,  1.5  per  cent,  65x4.1  (60-80  x  3.7-4.4) /x  (only  four 

measured) 
7-septate,  1.5  per  cent,  67x4.5  (62-72  x  4. 1-5.3)  ^  (only  four 

measured) 

On  wheat  grain  culture  sixteen  days  old;  conidia  from  aerial  mycelium: 

(1)  Sporotrichial  form 

Conidia:     0-septate,  70  per  cent,  11.4x5.6  (8-16  x  4-6.5) /* 
1-septate,  30  per  cent,  14  x  5.6  (11-17  x  4.8-6)m 

(2)  Sickle-shaped  form 

Conidia:     0-septate,  9  per  cent,  10  x  3.2^t 

1-septate,  68  per  cent,  20  x  3.8  (12-24  x  3-4.2) m 

2-septate,  5  per  cent 

3-septate,  18  per  cent,  32  x  4.3  (24-44  x  3.9-4.7) m 

Average  of  the  above  measurements : 

(1)  Sporotrichial  form 

Conidia:  0-septate,  83  per  cent,  10.5  x  6/i 
1-septate,  17  per  cent,  14  x  5.4/x 
2-  and  3-septate,  rare  to  very  rare 

(2)  Sickle-shaped  form 
Conidia:     0-septate,  10  per  cent 

1-septate,  31  per  cent,  10  x  3.1/x 

2-septate,  2  per  cent 

3-septate,  36  per  cent,  30.4  x  3.8/i 

4-septate,  6  per  cent 

5-septate,  13  per  cent,  50.5  x  4.3iU 

6-  to  10-septate,  2  per  cent,  about  67  x  4.5ai 

VIII.  Section  FERRUGINOSUM  n.  sec. 

Conidia  mostly  of  an  intermediate  type,  between  that  of  section 
Gibbosum  and  section  Roseum,  3-  to  7-septate;  intercalary  chlamy do- 
spores  typically  present.  Substratum  and  basal  layer  of  aerial  mycelium 
varying  from  white  when  young  to  different  hues  of  red  at  maturity. 

27.  Fusarium  arcuosponim  n.  sp.  (Figs.  iBiand  23;  PI.  ii,  figs.  7  and  8; 
PI.  VI,  fig.  10) 

Conidia   very   gradually   pointed   toward   apex,    disthictly   and   often 


FusARiA  OF  Potatoes 


187 


prominently  pedicellate,  typically  much  arcuate,  5-septate,  49.2  x  4 
(42-54  X  3.6-4.2) ;u,  also  often  from  3-  to  7-septate;  single  on  aerial 
conidiophores  and  in  from  small  to  medium  (up  to  1.5  millimeters  in 
diameter)  sporodochia,  the  latter  sometimes  converging  into  pseudo- 
pionnotes;  intercalary  chlamydospores  in  mycelial  threads  typically 
present,  though  not  numerous,  and  single  or  only  in  small  clusters  of  from 
two  to  four  cells;  aerial  mycelium  usually  well  developed,  uniform,  white 
at  first,  then,  on  substrata  poor  in  glucose,  of  different  tints  of  pink  with 
the  substratum  of  a  pomegranate  color  of  different  density;  on  potato 
agar  rich  in  glucose,  color  as  shown  in  Plate  ii,  figures  7  and  8. 


Fig.  23. —  Fusarium  arcuosporum.  a,  Sporodochial  conidia,  b,  conidiophore,  from  20-days- 
old  culture  on  hard  lima-hean  agar  with  2  per  cent  glucose;  c,  conidia  from  small  aerial  sporo- 
dochium  from  ^9-days-old  culture  on  whole  steamed  potato  tuber;  d,  typical  conidium  {the  long 
one)  and  abnormal  pseudopionnotal  conidium  from  11 -days-old  hard  potato  agar;  e,  aerial 
conidia,  f,  chlamydospores,  g,  conidiophores,  from  75-days-old  culture  on  red  raspberry  cane 
plug;  H,  pseudopionnotal  conidia,  i,  conidiophores,  from  12-days-old  culture  on  slightly  acidified 
hard  potato  agar;  3,  conidiophore,  k,  chlamydospores,  l,  conidial  ball,  m,  conidiophores,  from 
aerial  mycelium  from  75-days-old  culture  on  red  raspberry  cane  plug;  n,  chlamydospores  from 
173-days-old  culture  on  corn  agar;  o,  peculiarly  branched,  p,  normal,  pseudopionnotal  conidia 
from  14-days-old  culture  on  hard  lima-bean  agar;  q,  conidia  from  aerial  sporodochium  of  107- 
days-old  culture  on  potato  stem  plug;  n,  conidia  from  109-days-old  culture  on  rye  straw;  s,  typical 
sporodochial  conidium  from  24-days-old  culture  o/i  potato  tuber  plug;  t,  chlamydospores  from 
109-days-old  culture  on  rye  straw 


Hab.     On  rotted  tubers  of  Solanuni  tuberosum,   in   association   with 
F.  anguioides,  Castile,  New  York. 


188  C.  D.  Sherbakoff 

Latin  description. — Conidiis  maxime  gradatim  in  apicem  acutis,  dis- 
tincte  vel  saepe  insignite  pedicellatis,  typice  magnopere  arcuatis,  5-sep- 
tatis,  49.2  x  4  (42-54  x  3.6-4.2) /x,  etiam  saepe  3-7-septatis;  continuis  in 
aeriis  conidiophoris  vel  minutis  mediocribusve  (usque  ad  ^  mm.  diam.) 
sporodochiis  in  pseudopionnotes  interdum  vergentibus;  chlamydosporis 
intercalaribus  sed  non  plurimis,  continuis  vel  tantum  minutis  uveosis, 
1-3-septatis ;  aerio  mycelio  fere  plene  mature,  unif ormi,  primum  albo,  dein, 
in  substratis  parum  glucosis,  rubello  varie  tincto,  substrate  "  pome- 
granate" (R);  in  Solani  tuberosi  agare  perglucoso,  colore  Tab.  ii,  figg.  7,  8, 
exhibito. 

Hab.  In  tuberibus  putridis  Solani  tuberosi  una  cum  F.  anguioide, 
Castile,  New  York,  Amer.  bor. 

Measurements  of  conidia  on  different  media  are  as  follows: 
.     On  slightly  acidified  hard  potato  agar,  culture  twelve  days  old;  conidia 
from  aerial  mycelium: 
Conidia:     0-  and  1-septate,  rare,  immature 

3-septate,  17  per  cent,  43x3.5  (35-56  x  3-4.1  )/x 
4-septate,  19  per  cent,  49  x  3.5  (38-59  x  3-4. IV 
5-septate,  64  per  cent,  54  x  3.7  (40-74  x  3-4.4)/x 

On  red  raspberry  cane  plug,  culture  seventy-five  days  old;  conidia  from 

aerial  mycelium: 

Conidia:     3-septate,  10  per  cent,  45  x  3.4  (28-51  x  3-4) ju 
4-septate,  30  per  cent,  50  x  3.5  (36-62  x  3-4.3) m 
5-septate,  60.per  cent,  53  x  3.6  (44-62  x  3.5-4)/x 
On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  seven  days  old ; 

conidia  from  aerial  mycelium : 

Conidia:     3-septate,  30  per  centl  (granulation  of  the  protoplasm  was  too 
4-septate,  15  per  cent]      great  to  clearly  distinguish  septation) 
5-septate,  55  per  cent,  53x3.8  (45-62  x  3.4-4.4) /x 
On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  twenty  days 

old;   conidia  from  pseudopionnotes: 

Conidia:     0-septate,  rare 
1-septate,  rare 

4-septate,  4  per  cent,  47  x  4.2jLt  (only  two  measured) 
5-septate,  95  per  cent,  54  x  4  (47-63  x  3. 5-4.8) /x 
6-septate,  1  per  cent,  52x4.1/^  (only  two  measured) 


FusA«RiA  OF  Potatoes  189 

On  potato  tuber  plug,  culture  twenty-four  days  old;  conidia  from  aniall 
sporodochia : 
Conidia:     1-septate,  1  per  cent,  about  14  x  3.5ju  (only  one  measured) 

3-septate,  10  per  cent,  35  x  3.6  (27-43  x  3-4.4) m 

4-septate,  12  per  cent 

5-septate,  77  per  cent,  45  x  4  (35-51  x  3.3-4.8) /x 

6-  and  7-septate,  rare,  52  x  4.5/x  (only  two  measured) 

On  potato  stem  plug,  culture  one  hundred  and  seven  days  old;  conidia 
from  aerial  mycelium: 
Conidia:     0-septate,  rare 

1-septate,  2  per  cent 

2-septate,  rare 

3-septate,  50  per  cent,  31  x  3.7/x 

4-septate,  25  per  cent,  40  x  4/i 

5-septate,  23  per  cent,  42  x  4.2  (35-48  x  3.9-4.7) ^ 

On  whole  steamed  potato  tubers,   culture  forty-nine  days  old : 

(1)  Conidia  from  numerous  small  sporodochia,  close  to  the  substratum 
Conidia:     3-septate,  6  per  cent,  about  30  x  3.5  (only  a  few  spores  measured) 

4-septate,  6  per  cent 

5-septate,  80  per  cent,  46  x  4.1  (40-53  x  3.9-4. l)/x 
6-septate,  5  per  cent,  54x4.1  (42-65  x  4-4.7)  m 
7-septate,  3  per  cent,  59  x  4.2  (48-65  x  4. 1-4.5) m 
10-septate,  only  one  was  observed,  58  x  4.3/i  (the  largest) 

(2)  Conidia  from  small  sporodochia,  in  aerial  mycelium 
Conidia:     3-septate,  rare 

4-septate,  rare 

5-septate,  nearly  100  per  cent,  51  x  4  (45-55  x  3.6-4.3)jtt 

6-septate,  rare 

On  medium  soft  agar,   culture  eleven  days  old;    conidia   from   aerial 
mycelium  close  to  substratum : 
Conidia:     1-septate,  2  per  cent,  24  x  3.2  (only  a  few  measured) 

3-septate,  8  per  cent,  42  x  4/x  (only  a  few  measured) 

4-septate,  10  per  cent 

5-septate,  77  per  cent,  45  x  4.1  (41-62  x  3. 1-4.8)  yu 

6-septate,  3  per  cent,  49  x  4,3/i  (only  a  few  measured) 


190  C.  D.  Sherbakoff 

On  hard  lima-bean  agar,  culture  fourteen  days  old ;  conidia  from  minute 

converging   sporodochia    close   to   substratum: 

Conidia:     3-septate,  3  per  cent 
4-septate,  1  per  cent 

5-septate,  95  per  cent,  49  x  4.2  (41-63  x  3.5-5.3)m 
6-septate,  1  per  cent,  54  x  4.7^  (only  a  few  measured) 

Average  of  the  above  measurements: 
Conidia:     0-  to  2-septate,  very  rare 

3-septate,  13  per  cent,  38  x  3.5m 
4-septate,  13.5  per  cent 
5-septate,  72.5  per  cent,  49.2  x  4/i 
6-  and  7-septate,  1  per  cent,  53.6  x  4.3^ 

The  organism  occupies  an  intermediate  position  between  section  Roseum 
and  section  Ferruginosum;  its  type  of  conidia  is  that  of  section  Roseum, 
while  because  of  its  true  chlamydospores  of  only  an  intercalary  kind  it 
belongs  to  the  section  Ferruginosum. 

An  especially  striking  peculiarity  of  F.  arcuosporum  is  the  frequent 
occurrence,  especially  in  young  cultures  on  various  agars,  of  conidia  with 
more  or  less  distinct  branches  and  knobs  (Fig.  23  o). 

28.  Fusarium  ferruginosum  n.  sp.  (Figs.  1,  h  to  J,  and  24;  PI.  iii, 
figs.  9  and  10;  PI.  vi,  fig.  2) 

Conidia  well  developed,  in  from  small  to  medium-sized  (up  to  2  milli- 
meters in  diameter)  sporodochia  or  hi  pseudopionnotes,  very  gradually 
pointed  toward  apex,  distinctly  pedicellate,  more  or  less  strongly  arcuate, 
and  broader  in  the  middle  or  in  the  lower  third  of  their  length,  typically 
3-  to  5-septate;  5-septate  average  45.3x4.2  (28-53  x  4. 1-4.2) /x;  conidia 
from  aerial  mycelium  —  sometimes  also  from  sporodochia  produced  on 
very  old  agar  cultures  —  typically  3-septate,  30.8  x  3. 8^,  mostly  apedicellate; 
conidia  from  nearly  white  to  pale  pink  buff  and  deep  vinaceous  in  color; 
intercalary  chlamydospores  in  mycelium  always  present,  often  very 
numerous,  in  long  chains  and  large  clusters;  aerial  mycelium  always 
well  developed,  high,  often  very  dense,  white  at  first  changing  to  pink 
and  then  ferruginous  when  mature,  the  last-named  color  being  due  to 
production  of  great  masses  of  chlamydospores;  color  of  substratum,  on 


FusARiA  OF  Potatoes 


191 


potato  agar  rich  in  glucose,  at  first  pink,  then  ochraceous  tawny,  and 
finally  ferruginous  and  Hay's  russet, 

Hab.  On  rotted  tubers  of  Solarium  tuberosum,  Long  Island,  New  York, 
on  Ly coper sicu7n  esculentum,  Virginia,  and  on  Panax  quinquefolium,  New 
York  State. 

Latin  description. — Conidiis  plene  maturis — sporodochiis  minutis  .  vel 
mediocribus  (usque  ad  2  mm.  diam.)  vel  pseudopionnotibus  —  maxime 
gradatim  in  apicem  acutis,  distincte  pedicellatis,  plus  minusve  valide 
arcuatis,  latioribus  in  medio  vel  in  inferiore  tertio  longitudinis,  typice  3-5- 
septatis;  5-septatis  plerumque  45.3x4.2  (28-53  x  4. 1-4.2) /i;  conidiis 
in  aerio  mycelio  —  interdum  etiam  ex  sporodochiis  in  vetustissimis  agaris 


Fig.  24. —  Fusarium  ferruginosum.  a,  PseUdopionnotal  conidia  from  10-days-old  culture 
on  hard  lima-bean  agar:  b,  sporodochial  conidia  from  130-days-old  culture  on  hard  lima-hean 
agar  with  2  -per  cent  glucose;  c,  aerial  conidia  from  H-days-old  culture  on  slightly  acidified 
hard  potato  agar;  d,  pseudopionnotal  conidia  from  S-days-otd  culture  on  hard  lima-bean  agar; 
E,  aerial  conidia,  f,  chlamydospores,  from  35-days-old  culture  on  corn  meal;  G,  conidiophores 
from  3-days-old  culture  on  hard  lima-bean  agar 


culturis  crescentibus  —  typice  3-septatis,  30.8  x  3.8m,  plerumque  apedicel- 
latis;  conidiis  ex  albido  pallide  rubellis,  gilvis  atque  vinaceosis;  chlamy- 
dosporis  intercalaribus  semper  in  myceho  praesentibus,  saepe  plurimis, 
longis  catenulatis  longis  uveosisque;  aerio  mycelio  semper  plene  maturo, 
alto,  semper  densissimo,  primum  albo,  dein  rubello  demum  ferrugineo, 
quem  colorem  magnae  moles  chlamydosporum  ortae  efficiunt;  substrate 
in  agare  Solani  tuberosi  glucoso,  primum  rubello,  dein  "  ochraceous  tawny  " 
(R),  demum  ferrugineo  et  "Hay's  russet  "  (R). 

Hab.  In  tuberibus  putridis  Solani  tuberosi,  Long  Island,  New  York, 
in  Lycopersico  esculento,  Virginia,  et  in  Panaci  quinquefolio,  New  York, 
Amer.  bor. 

Measurements  of  conidia  on  different  media  are  as  follows: 


192  C.  D.  Sherbakoff 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  one  hundred 
and  thirty  days  old;  conidia  from  small  sporodochia   produced  after  the 
culture  was  over  eighty  days  old: 
Conidia:     0-septate,  very  rare,  9  x  2.8^ 

1-septate,  4  per  cent,  12  x  3.2/i 

2-septate,  3  per  cent,  17  x  3.5/i 

3-septate,  93  per  cent,  27.3  x  4.1  (17-33  x  3.8-4.4) ^ 

On  hard  potato  agar  with  10  per  cent  glucose,  culture  seven  days  old  in 
poured  plate: 

(1)  Chlamydospores 

0-septate,  10x9.5  (7-12.5  x  7-11. 5) m 
1-septate,  16  x  11/x 

(2)  Conidia  from  aerial  mycelium 
Conidia:     1-septate,  1  per  cent 

2-septate,  1  per  cent 

3-septate,  88  per  cent,  32  x  3.7  (25-40  x  3. 1-4.2) ^ 

4-septate,  6  per  cent 

5-septate,  4  per  cent,  38  x  4.1  (35-42  x  3.9-4.4) /x 

On  hard  lima-bean  agar,  culture  three  days  old;  conidia  from  pseudo- 
pionnotes  (near  the  center  of  inoculation) : 
Conidia:     3-septate,  66  per  cent,  36  x  3.9  (30-41  x  3.5-4.3)m 

4-septate,  20  per  cent 

5-septate,  14  per  cent,  45  x  4.2  (42-56  x  3.9-4.7)/i 

On  corn  meal  agar,  culture  thirty-five  days  old: 

(1)  Chlamydospores  typically  in  chains,  8.5  (5.8-15)^  in  diameter 

(2)  Conidia  from  aerial  mycelium 

Conidia:     0-septate,  20  per  cent,  8.8  x  2.6  (7-12  x  2.4-3) m 

1-septate,  46  per  cent,  12.8  x  2.9  (9-19  x  2.5-3.1)/x 
2-septate,  6  per  cent 

3-septate,  26  per  cent,  20.4  x  3.4  (17-30  x  3-3.8) m 
4-septate,  2  per  cent,  26.7  x  3.9  (24-29  x  3.7-4)/x 

On  hard  lima-bean  agar,  culture  ten  days  old;  conidia  from  pseudopion- 
notes: 

Conidia:     3-septate,  8  per  cent,  41  x  3.9/x 
4-septate,  12  per  cent,  45.5  x  4/i 


FusARiA  OF  Potatoes  193 

5-septate,  80  per  cent,  53x4.2  (50-58  x  4. 1-4.4) m,  the  largest 
observed  being  65  x  4.1/^ 

On  slightly  acidified  hard  potato  agar,  cuUure  fourteen  days  old;  conidia 

from  aerial  mycelium: 

Conidia:     0-septate,  26  per  cent,  10  x  2.5  (8-14  x  1.7-3.5)jLi 

1-septate,  41.5  per  cent,  17.3  x  3  (14-20  x  2.5-3.5)/* 
2-septate,  10  per  cent,  19.5  x  3.2  (15-31  x  2.9-4)m 
3-septate,  17.5  per  cent,  28  x  3.6  (19-42  x  2.9-4.7)/* 

4-septate,  3  per  cent  1  3^  ^  ^  ^  (30-15  x  3.9-5.2)/. 
5-septate,  2  per  cent  J 

Average  of  the  above  measurements: 
Conidia:     0-septate,  7.5  per  cent,  9.4  x  2.55/i 
1-septate,  14.5  per  cent,  13  x  3/x 
2-septate,  3  per  cent 
3-septate,  48  per  cent,  30.8  x  3.8/i 
4-septate,  10  per  cent,  38.8  x  4.03/* 
5-septate,  17  per  cent,  45.3  x  4.2/x 

The  organism  was  isolated  only  once  from  potato  tubers,  but  it  was 
isolated  by  the  writer  from  a  specimen  of  Rhizoctonia-infected  tomato 
plant  also,  from  Virginia,  and  by  C.  O.  Dalrymple  from  ginseng  garden 
soil  in  New  York  State.     This  seems  to  be  a  cosmopolitan  species. 

29.  Fusarium  sanguineum  n.  sp.  (Fig.  25;  PI.  iii,  figs.  7  and  8;  PI.  vi, 

fig.  1) 

Conidia  typically  strongly  arcuate,  gradually  pointed  toward  apex, 
distinctly  pedicellate,  3-  to  5-septate  —  3-septate  conidia  averaging 
33.5x3.6  (24-37  X  3.4-3.8) /i  and  5-septate  averaging  45.2x4.1  (40- 
47x3.9^.2)/* — -single,  in  from  small  to  medium-sized  (up  to  2  milli- 
meters in  diameter)  sporodochia  and  in  pseudopionnotes,  the  latter  form 
of  fructification  dominazit  on  most  media,  especially  on  agars;  chlamy do- 
spores  almost  always  present,  intercalary  in  conidia  and  in  myoelial 
threads,  borne  singly,  in  chains  and  in  clusters;  aerial  mycelium  seldom 
well  developed  and  then  from  white  to  different  shades  of  pink,  on  various 
agars  mostly  absent  leaving  exposed  pseudopionnotes  of  ox-blood  red 
color. 


194 


C.  D.  Sherbakoff 


Hab.  On  rotted  tubers  of  Solarium  tuberosum  in  association  with 
F.  lutulatum  var.  zonatum,  Ithaca,  New  York. 

Latin  description. — Conidiis  typice  vahde  arcuatis,  gradatim  in  apicem 
acutis,  distincte  pedicellatis,  3-5-septatis  —  conidiis  3-septatis,  33.5x3.6 
(24-37  X  3.4-3.8)m,  conidiis  5-septatis,  45.2x4.1  (40-47  x  3.9-4.2)/x  — 
continuis,  minutis  vel  mediocribus  (usque  ad  2  mm.  diam.)  sporodochiis 
et  pseudopionnotibus,  quo  fructificationis  modo  in  plurimis  mediis  fre- 
quentissimo  imprimis  in  agaribus;  chlamydosporis  plerumque  praesentibus, 
intercalaribus  in  conidiis  et  in  hyphis,  singulatim  ortis,  catenulatis  vel 
uveosis;  aerio  myceho  raro  plene  maturo,  sed,  cum  plene  maturum,  tum 


Fig.  25. —  Fusarium  sanguineum.  a,  Pseudopionnotal  conidia  (one  chlamydospore-like 
conidium)  from  8-days-old  culture  on  hard  linia-bean  agar  ivitk  2  per  cent  glucose;  b,  pseudo- 
pionnotal conidia  from  IJ^-daijs-old  culture  on  hard  lima-bean  agar;  c,  typical  conidium  from 
47-days-old  culture  on  whole  grains  of  wheat;  d,  pseudopionnotal  conidia  from  19-days-old 
culture  on  slightly  acidified  hard  potato  agar;  e,  pseudopionnotal  conidia  from  23-days-old 
culture  on  red  raspberry  cane  plug;  F,  conidia,  G,  chlamydospores,  from  76-days-old  culture 
on  potato  tuber  plug;  H,  conidiophores  from  23-days-old  culture  on  red  raspberry  cane  plug; 
I,  chlamydospores  from  176-days-old  culture  on  corn  agar;  j,  sporodochial  conidia  from  J^l -days- 
old  culture  on  rye  straw;  k,  conidia  from  176-days-old  culture  on  corn  meal;  l,  conidiophores 
from  47-days-old  culture  on  whole  grains  of  wheat 


ex  albo  varie  rubello  tincto,  in  agaribus  variis  plerumque  absente,  pseudo- 
pionnotes  "  ox-l^lood  red "   (R)  exponente. 

Hab.  In  tuberibus  putridis  Solani  tuberosi  una  cum  F.  lutulato  var. 
zonato,  Ithaca,  New  York,  Amer.  bor. 

Measurements  of  conidia  on  different  media  are  as  follows: 


FusARiA  OF  Potatoes  195 

On  red  raspberry  cane  plug,  culture  twenty-three  days  old: 

(1)  Conidia  from  pseudopionnotes 

Conidia:     1-septate,  7  per  cent,  15  x  2.3  (10-23  x  2.2-2.5) fx 
2-septate,  2.5  per  cent 

3-septate,  17  per  cent,  32  x  3.4  (22-43  x  2.8-4.1)/i 
4-septate,  7  per  cent,  40  x  3.8  (35-45  x  3-4.3)^ 
5-septate,  63.5  per  cent,  47  x  4.2  (38-51  x  3.9^.3)/i 
6-septate,  3  per  cent,  52-60  x  4.1-4.4)u  (only  a  few  measured) 
7-septate,  very  few,  52-60  x4.1-4.4/x  (only  a  few  measured, 
the  thickest,  swollen,  6.2/i  in  diameter) 

(2)  Chlamydospores 

(a)  Unicellular,  in  conidia,  6-12.5  x  6-8/i 

(b)  Unicellular,  in  mycelium,  8-17  x  7-14/i 

On  slightly  acidified  hard  potato  agar,  culture  nineteen  days  old;  conidia 

from  pseudopionnotes: 

Conidia:     1-septate,  1  per  cent 
2-septate,  2  per  cent 

3-septate,  57  per  cent,  37.5  x  3.6  (32-50  x  3-4)/* 
4-septate,  17  per  cent,  44  x  3.7  (38-60  x  3.5-4.4)/x 
5-septate,  20  per  cent,  45  x  4.1  (40-60  x  3.8-4.4)/i 
6-septate 


_        ^  ^    r  3  per  cent 
7-septate  ' 

On  potato  tuber  plug,  culture  seventy-six  days  old;  conidia  from  aerial 
mycelium : 
Conidia:     0-septate,  5  per  cent 

1-septate,  15  per  cent 

2-septate,  10  per  cent 

3-septate,  55  per  cent,  24  x  3.5  (17-35  x  3-4)/i 

4-septate,  7  per  cent 

5-septate,  8  per  cent,  40  x  4.1  (35-43  x  3.5-4.4)/i 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  eight  days  old; 
conidia  from  pseudopionnotes: 
Conidia:     3-septate,  3  per  cent,  41  x  3.8  (35-44  x  3.5-4.1))u 

4-septate,  5  per  cent 

5-septate,  90  per  cent,  47  x  4.2  (43-51  x  3.9-4.7)/! 

6-septate,  2  per  cent 


196  CD.  Sherbakoff 

On  hard  lima-bean  agar,  culture  sixteen  days  old,  most  of  the  conidia 
swollen  (only  normal,  not  swollen,  conidia,  were  measured) : 
Conidia:     1-septate,  9  per  cent,  14.7  x  2.5  (12-19.5  x  2.3-3)m 
2-septate,  very  rare 

3-septate,  37  per  cent,  33  x  3.5  (18-41  x  3-4.1)/x 
4-septate,  14  per  cent 

5-septate,  29  per  cent,  47  x  3.9  (38-56  x  3.5-4.4)/i 
6-septate,  7  per  cent,  50x4  (43-58  x  3.9-4.4) m 
7-septate,  4  per  cent,  50  x  4.1  (49-56  x  4-4.3) At 
8-septate,  exceptional,  61  x  4.4/i  (only  one  found  and  measured) 

Average  of  the  above  measurements: 
Conidia:     0-septate,  1  per  cent 
1-septate,  6  per  cent 
2-septate,  3  per  cent 
3-septate,  34  per  cent,  33.5  x  3.6/i 
4-septate,  10  per  cent 
5-septate,  42  per  cent,  45.2x4.1/^ 
6-  and  7-septate,  4  per  cent,  50  x  4.05^1 
8-septate,  very  rare,  61  x  4.4iU  (only  one  measured) 

30,  Fusarium  sanguineum  var.  pallidium  n.  var.  (Figs.  Ik  and  26; 
PI.  Ill,  figs.  5  and  6;  PI.  vii,  fig.  7) 

Differs  from  F.  sanguineum  by  better  development  of  mycelium,  by 
much  slower  rate  of  colony  growth,  by  paler  color  of  substratum  and 
conidia  (PI.  iii,  figs.  5  and  6),  and  by  chlamydospores  which  are  inter- 
calary, as  in  F.  sanguineum,  but  mostly  in  conidia  and  not  in  mycelium, 
and  of  much  rarer  occurrence  than  in  F.  sanguineum. 

Hab.  On  rotted  tubers  of  Solanum  tuberosum,  in  association  with 
F.  oxysporum.  South  Dakota. 

Measurements  of  conidia  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  three  days  old;  conidia 

from  pseudopionnotes : 

Conidia:     2-septate,  rare 

3-septate,  53  per  cent,  45  x  3.9  (38-56  x  3.5-4.1)// 
4-septate,  20  per  cent,  40  x  4  (40-57  x  3.9-4. l))u 
5-septate,  20  per  cent,  53  x  4.1  (47-60  x  3.9-4.3) m 
6-  and  7-septate,  7  per  cent,  55  x  4.3  (52-61  x  4.1-4.8)^ 


FusARiA  OF  Potatoes 


197 


On  red  raspberry  cane  plug,  culture  thirty-two  days  old;  conidia  from 

aerial  mycelium: 

Conidia:     1-septate,  few 

3-septate,  43  per  cent,  30  x  3.8  (19-42  x  2.6-4.3)m 
4-septate;  36  per  cent,  36  x  4  (31^2  x  3.5-4.3)m 
5-septate,  21  per  cent,  39  x  4.1  (33-43  x  3.9-4.7)/x 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  eight  days  old; 

conidia  from  pseudopionnotes : 

Conidia:  3-septate,  60  per  cent,  41  x  3.7  (35-48  x  3.5-4.1)^ 
4-septate,  25  per  cent,  51  x  3.8  (44-60  x  3.5-4.1)m 
5-septate,  15  per  cent,  55  x  3.8  (52-56  x  3.5-4)/i 


Fig.  26. —  Fusarium  sanguineum  var.  pallidium.  a,  Pseudopionnotal  conidia  from  32-days- 
old  culture  on  red  raspberry  cane  plug;  b,  pseudopionnotal  conidia  from  3-days-old  culture  on 
slightly  acidified  hard  potato  agar;  c,  pseudopionnotal  conidia  with  densely  granulated  content 
and  indistinct  septation  from  8-days-old  culture  on  hard  lima-bean  agar  ivith  2  per  cent  glucose: 
D,  conidia  {normal,  swollen,  and  with  chlamydospores)  from  aerial  mycelium  from  SS-days-old 
culture  on  ivhok  steamed  potato  tubers;  e,  chlamydospore-like  swellings  in  mycelium  from  176- 
days-old  culture  on  corn  agar;  f,  g.  h,  conidiophores  from  14-days-old  culture  on  hard  lima- 
bean  agar;  i,  pseudopionnotal  conidia  from  35-days-old  culture  on  whole  steamed  potato  tubers; 
J,  pseudopionnotal  and  aerial  conidia  from  14-days-old  culture  on  hard  lima-bean  agar 


On  whole  steamed  potato  tuber,    culture  thirty-eight  days  old: 
(1)  From  a  tuft  of  conidiophores  over  dry  surface  of  the  tuber  ;'*^  type 
of  spores  very  much  like  that  of  F.  discolor  var.  triseptatum 
Conidia:     1-septate,  2  per  cent 

2-septate,  7  per  cent,  about  17  x  3.6/i 
3-septate,  72  per  cent,  24  x  4.5  (19-32  x  4-4.8)  m 

"  This  type  ia  very  difierent  from  the  general  type,  and  therefore  was  not  taken  into  account  for  average 
size  of  conidia. 


198  C.  D.  Sherbakoff 

4-septate,  15  per  cent,  26  x  4.7  (24-30  x  4.6-5.2) yu 
5-septate,  4  per  cent,  28x4.7  (26-32  x  4.2-5.2) /x,  the  largest 
45.5  x  5.2At 

(2)  From  pionnotes  over  the  cut  surface  of  the  tuber;  spore  type  close 

to  thdt  of  F.  arcuosporum 

Conidia:     3-septate,  68  per  cent,  41  x  3.2  (29-48  x  2.9-3.5)^ 
4-septate,  20  per  cent,  44  x  3.4  (36-51  x  3.2-4) ^ 
5-septate,  12  per  cent,  48  x  3.4  (40-57  x  3-3.7)m 

On  hard   lima-bean   agar,    culture    fourteen    days   old;    conidia   from 
pseudopionnotes : 
Conidia:     1-septate,  2  per  cent,  21  x  2.8/^  (only  three  measured) 

2-septate,  exceptional 

3-septate,  83  per  cent,  37  x  3.5  (33-42  [61  exceptional]  x  3-3.9) m 

4-septate,  12  per  cent 

5-septate,  3  per  cent,  47  x  3.8  (42-60  x  3.5-4) ^ 

On  the  same  medium  and  of  the  same  age  as  the  above,  but  from  a 
semi-dry  minute  sporodochium  near  the  upper  margin  of  the  slant : 
Conidia:     1-septate,  1  per  cent 

3-septate,  56  per  cent,  43  x  3.8  (37-48  x  3.5-4.1)^ 

4-septate,  29  per  cent 

5-septate,  14  per  cent,  44  x  3.9  (40-49  x  S.5-4:.2)fx 

31.  Fusarium  buUatum  n.  sp.  (Figs.  1ai  and  27) 

Conidia  typically  somewhat  less  arcuate  than  the  other  species  of  the 
same  section,  less  pointed  toward  the  apex,  and  broader,  usually  distinctly 
pedicellate,  mostly  5-septate,  42x4.3  (31-^7  x  4. 1-4.9) /x,  from  pale 
cream  to  salmon  in  color;  chlamydospores  intercalary  in  mycelium, 
mostly  in  chains  and  from  small  to  large  clusters;  aerial  mycelium  nearly 
always  well  developed,  of  uniform  medium  height  and  density,  nearly 
pure  white  in  color;  substratum  on  various  agars  from  colorless  to  a  tint 
of  light  buff. 

Hab.  On  rotted  tuber  of  Solanum  tuberosum,  together  with  F.  hullatum 
var.  roseum  and  with  F.  oxysporum  var.  resupinatum,  in  Iowa. 


FusARiA  OF  Potatoes 


199 


Latin  description. — Conidiis  typice  paulo  minus  arcuatis  quam  ceteris 
ejusdem  sectionis  speciebus,  minus  in  apicem  acutis,  latioribus,  plerumque 
distincte  pedicellatis,  plerumque  5-septatis,  42x4.3  (31-47  x  4. 1-4.9) /x, 
e  pallide  "cream  color"  (11)  "salmon  color"  (R);  chlamydosporis  inter- 
calaribus  in  mycelio,  plerumque  catenulatis,  parvis  vel  magnis  uveosis; 
aerio  mycelio  semper  plene  maturo,  uniformi  mediocri  altitudine  atque 
densitate,  ferme  pure  albo;  substrate  in  agaribus  variis  ex  hyalino  pallide 
luteolo  tincto. 

Hab.  In  tuberibus  putridis  Solani  tuberosi  una  cum  F.  bullato  var. 
roseo  et  cum  F.  oxysporo  var.  resupinato,  Iowa,  Amer.  bor. 


Fig.  27. —  Fusarium  buUatum.  a,  Pseudopionnoial  conidia  from  10-daijs-old  culture  on 
hard  lima-bean  agar;  b,  pseudopionnoial  conidia  from  77-days-old  culture  on  red  raspberry 
cane  plug;  c,  a  typical  conidium  from  51-days-old  culture  on  potato  tuber  plug;  v>,  conidia  from 
76-days-old  cidture  on  potato  tuber  plug;  e,  conidia  from  1 9-day s-old  culture  on  hard  lima-bean 
agar;  f,  pseudopionnotal  conidia  from  7-days-old  culture  on  hard  potato  agar;  g,  conidia,  h, 
chlamydospores,  from  42-days-old  culture  on  rye  straw;  i,  chlamydospores  from  77-days-old 
culture  on  red  raspberry  cane  plug;  J,  conidiophores  from  7-days-old  culture  on  hard  potato  agar; 
K,  conidiophore  from  10-days-old  culture  on  hard  lima-bean  agar;  l,  chains  of  chlamydospores 
from  175-days-old  culture  on  corn  agar 

Measurements  of  conidia  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  seven  days  old;  conidia 

from  pseudopionnotes : 

Conidia:  3-septate,  16  per  cent,  36  x  3.8  (29-50  x  3.5-4.9)ju 
4-septate,  19  per  cent,  43  x  4.1  (33-50  x  3.9^.9)^ 
5-septate,  65  per  cent,  45  x  4.4  (37-63  x  4. 1-4.9) /x 
6-  to  8-septate,  rare,  65  x  4.9  (60-82  x  4.7-5.3) m 


200  C.  D.  Sherbakoff 

On  red  raspberry  cane  plug,  culture  seventy-seven  days  old;  conidia 
from  aerial  mycelium  close  to  substratum: 
Conidia:     3-septate,  25  per  cent 

4-septate,  20  per  cent 

5-septate,  55  per  cent,  48  x  4.1  (42-53  x  3.5-4.4) m 

On  potato  tuber  plug,  culture  seventy-six  days  old;  conidia  from  aerial 
mycelium : 
Conidia:     1-septate,  5  per  cent 

2-septate,  10  per  cent 

3-septate,  45  per  cent,  31  x  3.7  (22-39  x  3.5-4.6)^ 

4-septate,  20  per  cent 

5-septate,  20  per  cent,  39  x  4.2  (35-45  x  4-4.4) ^ 

Same  as  preceding,  culture  eighty  days  old;  conidia  from  aerial  mycelium: 
Conidia:     0-septate,  1  per  cent 
1-septate,  4  per  cent 
2-septate,  1  per  cent 

3-septate,  40  per  cent,  30  x  3.7  (22-39  x  3.1-4.1)/i 
4-septate,  20  per  cent 

5-septate,  34  per  cent,  41  x  4.2  (35-49  x  3.5-4.7) m 
6-  to  9-septate,  rare  (the  largest,  9-septate,  56  x  5.7^) 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  nineteen  days 
old;  conidia  from  pseudcpionnotes: 

Conidia:     3-septate,  2  per  cent,  35  x  S.Six  (only  three  measured) 
4-septate,  1  per  cent,  38  x  3.9/i  (only  four  measured) 
5-septate,  97  per  cent,  47  x  4.4  (43-54  x  4-4.7) n 
6-septate,  rare,  51  x  4.5m  (only  three  measured,  48-53  x  4.3- 
4.8m) 

On  potato  stem  plug,  culture  one   hundred  and  fourteen   days   old; 
conidia  from  aerial  mycelium : 
Conidia:     3-septate,  16  per  cent 

4-septate,  14  per  cent 

5-septate,  70  per  cent,  41  x  4.35  (36-46  x  4-4.7)m 


•  FusARiA  OF  Potatoes  201 

On  hard  lima-bean  agar,  culture  ten  days  old;  conidia  from  pseudopion- 
notes : 
Conidia:     0-septate,  rare 

1-septate,  5  per  cent 

2-septate,  rare 

3-septate,  15  per  cent 

4-septate,  10  per  cent 

5-septate,  70  per  cent,  43  x  4.1  (35-50  x  3.8-4.7)/^ 

In  some  cases  5-septate  conidia  were  up  to  100  per  cent,  in  others 
conidia  of  lower  septation  were  as  high  as  50  per  cent.  Of  the  smaller, 
3-septate  conidia  were  dominant. 

On  rye  straw,  culture  fifty  days  old;  conidia  from  aerial  mycelium  close 
to  substratum: 
Conidia:     3-septate,  10  per  cent 

4-septate,  5  per  cent 

5-septate,  85  per  cent,  31.25  x  4.1  (27-36  x  3.9-4.6)/: 

Average  of  the  above  measurements : 
Conidia:     0-septate,  rare 

1-septate,  2  per  cent 

2-septate,  1.5  per  cent 

3-septate,  21  per  cent,  33  x  3.75/z 

4-septate,  15  per  cent 

5-septate,  60.5  per  cent,  42  x  4.3/x 

6-  to  8-septate,  very  rare,  58  x  4.7^ 

32.  Fusarium  hullahim  var.  roseum  n.  var.  (Fig.  28;  PI.  iii,  fig.  2) 

Differs  from  F.  hullatum  mainly  by  its  red  substratum  (on  agar  rich  in 
glucose,  see  Plate  iii,  figure  2)  and  by  higher  septation  of  conidia. 

Hab.     Same  as  that  of  F.  hullatum. 

This  organism  and  F.  hullatum  are  in  general,  especially  in  minute 
details  of  the  character  of  the  mycelium  and  in  the  chlamydospores, 
very  much  alike,  and  both  were  isolated  from  the  same  planting  of  diseased 
tissue  of  a  rotted  potato  tuber  and  separated  out  on  the  first  dilution. 
It  is  possible  that  they  represent  an  example  of  a  sudden  and  permanent 
variation  of  one  Fusarium  in  pure  culture. 


202 


C.  D.  Sherbakoff 


IX.  Section  Elegans  Wr.,  Phytopath.  3:28,  fig.  1,  e,  f,  s,  t,  u,v.  1913 
Fusaria  with  ellipsoidal,  0-  and  1-septate,  microconidia;  macroconidia 
typically  3-septate,  often  also  4-  or  5-septate,  more  or  less  gradually 
pointed  toward  apex,  pedicellate;  ehlamydospores  intercalary  and  terminal 
in  and  on  mycelial  hyphse,  always  present,  and  often  also  in  and  on  co- 
nidia:  color  of  conidia  mostly  pinkish  buff;  color  of  substratum,  and  of 
aerial  mycelium  when  present  (on  potato  agar  rich  in  glucose  and  on 
rice),  typically  of  various  vinaceous  hues,  from  light  pinkish  to  dense 
purple. 


Fig.  28. —  Fusarium  bullatum  var.  roseum.  a,  Pseudopionnotal  conidia  from  7-days-old 
culture  on  slightly  acidified  hard  -potato  agar;  b,  pseudopionnotal  conidia  from  9-days-old  culture 
on  hard  lima-hean  agar;  c,  pseudopionnotal  conidia  from  12-day s-old  culture  on  hard  lima-bean 
agar;  d,  sporodochial  conidia  from  71-days-old  cidture  on  potato  stem  plug;  E,  pseudopionnotal 
conidia  {many  are  swollen  and  tvith  oil  drops)  from  35-days-old  cxdture  on  corn  meal;  f.  conidia 
from  37-days-old  culture  on  hard  oat  gar;  g,  conidia  from  67-days-old  culture  on  red  raspberry 
cane  plug;  h,  pseudopionnotal  conidia  from  16-days-old  culture  on  hard  lima-bean  agar  {the 
two  at  the  left  typical  for  older  groicih,  the  one  at  the  right  for  young  groivth) ;  i,  ehlamydospores, 
intercalary  in  chains  and  in  clusters,  from  67-days-old  culture  on  red  raspberry  cane  plug; 
3,  ehlamydospores  from  12-days-old  culture  on  hard  lima-bean  agar;  k,  l,  m,  conidiophores 
from  7-days  old  culture  on  slightly  acidified  hard  potato  agar;  n,  conidiophores  from  12-days-old 
culture  on  hard  lima-bean  agar;  o,  conidiophores  from  35-days-old  culture  on  corn  meal 


33.  Fusarium  orthoceras  Ap.  et  Wr.  (Figs.  1,  ii  to  Ki,  and  29) 

Appel,  O.,  and  Wollenweber,  H.  W.    Arb.  K.  biol.  Anst.  Land-  u.  Fo  stw. 

8:141-156;  PI.  i,  figs.  60  to  64;  PI.  iii,  fig.  2.     1910.     Wollenweber,  H.  W., 

Phytopath.  3:30,  fig.  Is.     1913. 


FusARiA  OF  Potatoes 


203 


Microconidia  always  greatly  in  excess;  ma- 
croconidia  ranging  from  rare  to  several  per  cent 
of  the  total  number  of  conidia,  mostly  nearly 
straight,  sometimes  slightly  curved,  typically 
3-septate,  36x3.85  (25-iO  x  3.2-4) yu;  aerial 
mycelium  usually  well  developed,  from  white 
to  a  tint  of  olive-buff;  substratum,  on  potato 
agar  rich  in  glucose,  colorless  at  first,  then 
from  russet  vinaceous  to  deep  brownish 
vinaceous;  no  sporodochia;  no  pseudopion- 
notes;  no  sclerotia.  Not  the  same  as  F. 
oxysporiim. 

Hab.  Roots  and  tubers  of  Solanacese,  also 
on  various  other  hosts  and  in  soil,  in  Europe 
and  North  America. 

The  organism  was  not  isolated  by  the  writer. 
The  original  culture  was  obtained  from  the 
Centralbureau  der  Association   Internationale 


Fig.  29. —  Fusarium  orthoceras. 
A,  Conidia  from  1 8-day s-old 
culture  on  slightly  acidified 
hard  'potato  agar;  b,  conidia 
Jrom  26 -day s-old  culture  on 
-potato  tuber  plug;  c,  conidia 
from  15-days-old  culture  on 
hard  lima-bean  agar  with  2  per 
cent  glucose;  d,  chlamydospores 
from  18-day  s-old  culture  on 
slightly  acidified  hard  potato 
agar;  e,  conidia,  some  in  a 
ball,  with  conidiophore  of  com- 
mon type,  from  30-days-old 
culture  on  corn  agar;  f, 
chlamydospores  from  53-days- 
old  culture  on  potato  tuber  plug 

des  Botanistes,  Amster- 
dam, Holland,  and  was 
studied  in  conjunction 
with  the  other  Fusaria. 
The  above  description 
is  in  the  main  the  same 
as  that  given  by  Wol- 
lenweber. 


Fig.  30. —  Fusarium  angustum.  a,  Pseudopionnotal  conidia 
from  Jf-days-old  culture  on  slightly  acidified  hard  potato 
agar;  b,  conidiophores  from  surface  of  the  exposed  substratum 
from  25-days-old  culture  on  corn  agar:  c,  pseudopionnotal 
conidia  from  9-days-old  culture  on  hard  lima-bean  agar  with 
2  per  cent  glucose;  d,  pseudopionnotal  conidia  from  8-days- 
old  culture  on  hard  lima-bean  agar;  e,  microconida  from 
aerial  mycelium;  F,  chlamydospores  from  74-days-old  red 
raspberry  cane  plug;  G,  conidiophores  from  9-days-old  cul- 
ture on  hard  lima-bean  agar  mth  2  per  cent  glucose 


34.  Fusarium  angus- 
tum n.  sp.  (Figs.  1,  Gi 
and  Hi,  and  30) 

Conidia  gradually 
pointed  toward  apex, 
from  slightly  curved  to 
nearly  straight   or  an- 


204  CD.  Sherbakoff 

guiform,  usually  distinctly  pedicellate,  mostly  3-septate,  45.64  k  3.52 
(42-49  X  3.3-3.6)m,  often  0-  to  5-septate,  sometimes  6-  to  8-septate; 
on  various  agars  usually  producing  thin  pseudopionnotes,  otherwise 
very  similar  to  F.  oxysporum. 

Hab.  In  discolored  fibrovascular  bundles  of  tubers  of  Solarium  tube- 
rosum, Ithaca,  New  York. 

Latin  description.- — Conidiis  gradatim  in  apicem  acutis,  paulum  cur- 
vatis  vel  prope  rectis  anguiformibusque,  plerumque  distincte  pedicel- 
latis,  plerumque  3-septatis,  45.64x3.52  (42-49  x  3.3-3.6) m,  saepe  0-5- 
septatis,  interdum  6-8-septatis ;  in  variis  agaribus  tenues  pseudopionnotes 
plerumque  exhibentibus,  aliter  simillimis  F.  oxysporo. 

Hab.  In  tuberum  fasciculis  decoloratis  fibro-vascularibusque  Solani 
tuberosi,  Ithaca,  New  York,  Amer.  bor. 

Measurements  of  conidia  on  different  media  are  as  follows: 
On  slightly  acidified  hard  potato  agar,  culture  four  days  old;  conidia 
from  pseudopionnotes : 
Conidia:     0-septate,  6  per  cent,  12  x  2.5  (8-18  x  1.8-3.5)m 

1-septate,  7  per  cent,  32  x  2.9  (19-52  x  2.5-4.2) m 
2-septate,  2  per  cent,  32  x  2.7  (30-39  x  2.5-3) ^ 
3-septate,  44  per  cent,    42.2  x  3.3  (31-69  x  2.5-4.4)^ 
4-septate,  13  per  cent,    60.4  x  3.8  (47-70  x  3.5-4.4) /x 
5-septate,  27  per  cent,  63  x  3.9  (43-81  x  3.5-4. 1)^ 
6-  to  8-septate,  1  per  cent,  90  x  4.1  (80-102  x  4-4.4)^ 
On  red  raspberry  cane  plug,  culture  seventy-four  days  old : 
Conidia:     0-septate,  90  per  cent 
1-septate,  7  per  cent 
3-septate,  3  per  cent,  39.4  x  3.81  (30-50  x  3-4.8) m 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  nine  days  old; 
conidia  from  pseudopionnotes: 
Conidia:     0-septate,  54  per  cent,  10  x  2.8  (5-15  x  2.7-3. l)/i 

1-septate,  7  per  cent,  18  x  2.9  (15-22  x  2.7- 3. 1)^ 

2-septate,  3  per  cent 

3-septate,  20  per  cent,  43  x  3.6  (29-53  x  3^.1)/x 

4-septate,  8  per  cent 

5-septate,  8  per  cent,  59  x  4.5  (52-70  x  3.9-4.8)ai 

6-septate,  few,  70  x  4.7/i  (only  one  measured) 


FusARiA  OF  Potatoes  205 

On  hard  lima-bean  agar,  culture  eight  days  old;  conidia  from  pseudo- 

pionnotes  (measurements  made  in  April) : 

Conidia:  0-septate,  39  per  cent,  11  x  2.6  (8.7-14  x  2. 1-3.2) /x 
1-septate,  17  per  cent,18  x  3.2  (14-23  x  2.9-3.9)^ 
2-septate,  3  per  cent,  24  x  3.3ju  (only  four  measured) 
3-septate,  32  per  cent,  49  x  3.6  (42-55  x  3.5-4.8)/x 
4-septate,  2  per  cent,  53  x  4ju  (only  four  measured) 
5-septate,  6  per  cent,  58  x  4.3  (52-65  x  3.5-4.8) /x 
6-septate,  1  per  cent,  73  x  4.7/*  (only  one  measured) 

On  same  media,  culture  nine  days  old  (measurements  made  in  May) : 
Conidia:     0-septate,  11  per  cent,  10  x  2.5  (5-15  x  1.6-3.3)iu 
1-septate,  9  per  cent,  17  x  3.1  (12-24  x  2.6-4)^ 
2-septate,  1  per  cent 

3-septate,  43  per  cent,  49  x  3.6  (31-54  x  2.7-4.1)/x 
4-septate,  13  per  cent 
5-septate,  23  per  cent,  50  x  4  (54-71  x  3.5-4.7)// 

Average  of  the  above  measurements: 
Conidia:     0-septate,  27.5  per  cent,  11  x  2.6/i 
1-septate,  10  per  cent,  21  x  3/i 
2-septate,  2  per  cent,  28  x  3/t 
3-septate,  35  per  cent,  45.64  x  3.52/t 
4-septate,  9  per  cent,  56.7  x  3.9/t 
5-septate,  16  per  cent,  60  x  4.2/i 
6-septate,  0.5  per  cent,  78  x  4.5/i 
8-septate,  very  rare,  78  x  4.5/i 

35.  Fusarium  redolens  Wr.*^  var.  Solani  n.  var.  (Figs.  1pi  and  31;  PI.  ii, 
figs.  3  and  4;  PI.  V,  fig.  2) 

Macroconidia  typically  more  or  less  gradually  attenuate,  sometimes  sud- 
denly constricted  at  the  apex,  pedicellate,  typically  broader  toward  and 


« Fusarium  redolens  Wr.  is  described  by  its  author  (see  WoUenweber,  Phytopath.  3  :  29-30,  fig.  1  e, 
1913)  as  follows:  "Differs  from  all  the  above-mentioned  species  [F.oxysporum,  F.  tracheiphijum,  P. 
lasinfedum,  F.  vasinfectum  var.  inodoratum,  F.  lycopersici,  and  F.  niveum]  in  the  large  size  of  its  triseptate 
conidia,  30-40  x  4.5-5.5/j,  and  in  the  color  of  the  brownish  white  conidial  massss.  A  lilac  odor  is  produced 
on  rice  and  milk.  No  blue  sclerotia.  Vascular  parasite,  cause  of  wilt  and  foot  disease  of  Pimm  sativum. 
Distribution  unknown." 


206 


C.  D.  Sherbakoff 


more  curved  near  apex,  3-septate,  36.4  x  4.86  (31-41  x  4.3-5)/x,  often 
also  4-  and  5-septate,  usually  in  numerous  from  small  to  medium  (up  to 
2|  millimeters,  commonly  |  millimeter,  in  diameter)  sporodochia, 
sometimes,  especially  on  different  agars  and  in  an  early  stage  of  culture 
growth,  in  pseudopionnotes;  from  nearly  white  in  color  when  in  small 
powdery  masses,  to  a  bright  orange  color  when  in  comparatively  large 
sporodochia  on  nearly  dry  potato  stems;  mostly,  however,  from  a  light 
pinkish  cinnamon  to  a  pinkish  buff;  aerial  mycelium  sometimes  medium 
well  developed  but  usually  very  scant,  short,  from  white  to  somewhat  gray- 
ish or  brownish  gray  in  color  (PI.  ii,  fig.  3);  color  of  substratum,  on  agar 
rich  in  glucose,  as  shown  on  Plate  ii,  figure  4,  which  is  different  from  all 
the  other  Fusaria  of  the  section  Elegans. 


Fig.  31. —  Fusarium  redolens  var.  Solani.  A,  Chlamydospores  produced  by  conidia  and 
mycelium  from  1 20-day s-old  culture  on  potato  stem  plug;  b,  conidiophores  from  H-days-old 
culture  on  slightly  acidified  hard  potato  agar;  c,  anastomosed  conidia  from  13 -days-old  culture 
on  hard  lima-bean  agar;  d,  sporodochial  conidia  from  35-days-old  culture  on  potato  stem  plug; 
E,  pseudopionnotal  conidia,  f,  conidiophores,  from  H-days-old  culture  on  slightly  acidified 
hard  potato  agar;  g,  sporodochial  conidia  from  63-days-old  culture  on  whole  grain  of  rye;  it,  normal 
pseudopionnotal  conidia  from  13-days-old  culture  on  hard  lima-bean  agar;  i,  pseudopionnotal 
conidia  from  9-days-old  culture  on  hard  lima-bean  agar  with  2  per  cent  glucose  (the  longest  spore 
is  typical);  j,  pseudopionnotal  conidia  from  120-days-old  culture  on  potato  stem  plug;  k,  spo- 
rodochial conidia  from  48-days-old  culture  on  red  raspberry  cane  plug 


Hab.     On  rotted  tubers  of  Solarium  tuberosum,  Atlanta,  New  York. 
Differs  from  F.  redolens  Wr.  by  somewhat  narrower  conidia  and  by 
color  of  substratum,^^  especially  on  potato  agar  rich  in  glucose. 
Measurements  of  spores  on  different  media  are  as  follows: 

■•6  Wollenweber  does  not  directly  give  color  of  substratum  of  his  F.  redolens,  but  judging  from  his  definite 
negative  statcmpnt  in  regard  to  F.  conglutinans  Wr.  it  appears  evident  that  F.  redolens  does  not  differ  notice- 
ably in  color  from  F.  oxysporum  and  the  majority  of  other  species  of  the  section  Elegans. 


FusARiA  OF  Potatoes  207 

On  slightly  acidified  hard  potato  agar,  culture  fourteen  days  old;  conidia 

from  pseudopiomiotes : 

Conidia:     2-septate,  0.5  per  cent,  26  x  4.7/1 

3-septate,  93.5  per  cent,  36  x  5  (26^9  x  4.3-5.8) m 
4-septate,  6  per  cent,  41.6  x  5.3  (38^6  x  4.9-6.1)ai 
5-  and  6-septate,  rare,  43-53  x  5-6At 

On  red  raspberry  cane  plug,  culture  forty-eight  days  old;  conidia  from 
a  small  sporodochium : 
Conidia:     0-septate,  2  per  cent 

1 -septate,  1  per  cent 

3-septate,  97  per  cent,  35.6  x  5  (28^5  x  4-5.9)/z 

On  hard  lima-bean  agar,  culture  nine  days  old;  conidia  from  pseudo- 
piomiotes : 
Conidia:    0-septate,  17  per  cent,  10  x  3.6  (6-16  x  3-4.3) fx 

1-septate,  10  per  cent,  20  x  3.9  (14-28  x  3.5-4.7) m 

2-septate,  3  per  cent 

3-septate,  70  per  cent,  34  x  4.9  (28-43  x  4.3-5.3) /z 

4-septate,  rare 

On  potato  tuber  plug,  culture  ninety-nine  days  old ;  conidia  from  a  me- 
dimn  small  sporodochium: 
Conidia:     2-septate,  rare,  27  x  4.8/z 

3-septate,    100  per  cent,  33.6  x  4.9  (29-39  x  4.6-5.7)/i 

On  potato  stem  plug,  culture  one  hundred  and  thirteen  days  old: 

(1)  Chlamydospores,  mostly  unicellular 
Chlamydospores:     0-septate,  6.5  x  6.1  (4.7-11  x  5.2-7. 5)At 

(2)  Conidia  from  a  sporodochium 
Conidia:     0-  and  1-septate,  very  rare 

3-septate,  100  per  cent,  34.5  x  4.5  (24-39  x  3.9-5.  1)m 
4-septate,  very  rare,  about  the  same  size  as  3-septate 

On  whole  steamed  potato  tuber,  culture  forty-nine  days  old;  conidia 
from  a  medium  small  sporodochium: 
Conidia:     0-  and  1-septate,  rare 

3-septate,  100  per  cent,  31  x  4.3  (29-36  x  4.1-4.8)At 


208  C.  D.  Sherbakoff 

On  rye   grain,    culture   sixty-three   days   old;    conidia    from    a    small 
sporodochium : 

(1)  Conidia:    0-septate,  5  per  cent 

1-septate,  3  per  cent 

2-septate,  1  per  cent 

3-septate,  91  per  cent,  34.6  x  4.6  (28-41  x  3.8-5.2) ^ 

4-septate,  rare 

5-septate,  very  rare 

(2)  Chlamydospores  in  mycelium,  terminal,  about  the  same  size  as  those 
on  potato  stem  plug 

On  corn  agar,  culture  one  hundred  and  seventy-three  days  old,  chlamy- 
dospores intercalary  and  terminal : 

Chlamydospores:     0-septate  (in  conidia),  9.4  x  8.3  (7-11  x  5.2-9)/i 
1-septate  (in  mycelium),  15  x  9  (11-20  x  7-ll)/x 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  one  hundred 
and  eighteen  days  old : 

(1)  Chlamydospores  not  numerous;  in  conidia,  0-septate,  8.7  x  8.5ju;  in 
mycelium,  0-  and  1-septate,  and  also  in  small  clusters  of  three 

(2)  Sporodochial  conidia 
Conidia:     1-septate,  rare 

3-septate,  94  per  cent,  37  x  5  (28-44  x  4.6-5.9) /t 
4-septate,  6  per  cent,  40  x  5.05  (37-44  x  4.7-5.9) ;u 
5-septate,  rare,  about  the  same  size  as  4-septate 

On  hard  lima-bean  agar,   culture  five  days  old;   chlamydospores   (in 
conidia)  not  observed;  conidia  from  pseudopionnotes : 
Conidia:     0-septate,  10  per  cent,  11  x  S.Qix 

1-septate,  3  per  cent,  22  x  4^1 

2-septate,  1  per  cent 

3-septate,  86  per  cent,  41  x  4.9  (33-53  x  4.6-5.2) /x 

4-septate,  rare 

5-septate,  very  rare 

On  the  same  medium  as  above,  culture  thirteen  days  old;  conidia  from 

pseudopionnotes : 

Conidia:     0-septate,  rare 

3-septate,  97  per  cent,  41  x  4.9  (34-49  x  4.2-5.2)m 
4-septate,  3  per  cent,  43  x  5  (36^8  x  4.7-5.2) )u 
5-septate,  rare,  45  x  5.1  (43^7  x  4.8-5.2) ^ 


FusARiA  OF  Potatoes 


209 


Average  of  the  above  measurements : 
Conidia:     0-septate,  3.5  per  cent,  10.5  x  3.6/x 
1-septate,  1.5  per  cent,  21  x  3.95m 
2-septate,  0.5  per  cent,  26.5  x  4.75m 
3-septate,  93  per  cent,  36.4  x  4.86m 
4-septate,  1.5  per  cent,  41.5  x  5.12m 
5-septate,  rare,  44.3  x  5.2m 
6-septate,  very  rare 

36.  Fusarium  lutulatum  n.  sp.  (Figs.  1fi  and  32;  PL  ii,  figs.  5  and  6; 
PL  V,  fig.  3) 


Fig.  32. —  Fusarium  lutulatum.  a,  Conidia  from  pledenchymic  sporodochium  from  60- 
days-old  culture  on  red  raspberry  cane  plug;  b,  pseudopionnotal  conidia  from  9-days-old  culture 
on  hard  lima-bean  agar  with  2  per  cent  glucose;  c,  pseudopionnotal  conidia  from  5-days-old 
culture  on  hard  lima-bean  agar;  d,  sporodochial  conidia  from  63-days-old  culture  on  whole  grain 
of  rye;  e,  sporodochial  conidia  from  49-day s-old  culture  on  whole  steamed  potato  tuber;  f,  pseudo- 
pionnotal conidia  from  23-days-old  culture  on  slightly  acidified  hard  potato  agar;  g,  h,  i,  j, 
conidiophores  from  5-days-old  culture  on  hard  lima-bean  agar;  k,  conidiophores  from  23-days- 
old  culture  on  slightly  acidified  hard  potato  agar;  l,  terminal  and  intercalary  chlamydospores 
from  63-days-old  culture  on  whole  grain  of  rye;  u,  chlamydospores  from  25-days-old  culture 
on  corn  agar 


Macroconidia  gradually  attenuate  toward  the  apex,  usually  distinctly 
pedicellate  and  uniformly  curved  throughout,  without  stronger  curvature 
near  apex,  typically  3-septate,  34x4  (28-38  x  3.7-4. 5)m,  also  2-  to  5- 
septate;  from  small  to  medium  sporodochia  (up  to  2  millimeters  in  diam- 
eter), often  converging  into  pseudopionnotes ;  aerial  mycelium,  when 
present,  short,  (mostly  from  I  to  2  millimeters  high),  white,  often,  especially 
on  agars  in  plate  cultures,  absent;  color  of  conidia  from  nearly  white 


210  C.  D.  Sherbakoff 

(on  aerial  mycelium  in  the  form  of  coarse  powder)  to  dark  vinaceous 
purple;  typical  variation  of  spore  color  shown  in  Plate  ii,  figures  5  and  6; 
sometimes  on  potato  stem  plug,  from  one  to  a  few  large  sporodochia 
(2  millimeters  in  diameter)  of  a  bright  orange  color  produced;  substratum 
from  colorless  to  that  of  the  conidial  masses;  small  bluish  black  sclerotia 
(I  millimeter  in  diameter)  sometimes  produced,  and  then  in  great  num- 
bers all  over  the  substratum  (on  potato  tuber  plug);  zonation  of  colony 
very  faint  or  none  on  neutral  agars  in  plate  cultures. 

Hab.  On  soft  and  dry  rotted  tubers  of  Solarium  tuberosum,  Atlanta, 
New  York. 

Latin  description. — Macroconidiis  gradatim  in  apicem  attenuatis,  pler- 
umque  distincte  pedicellatis  et  aequabiliter  curvatis,  non  ad  apicem 
curvatioribus,  typice  3-septatis,  34x4.23  (28-38  x  3.7-4.5)iu,  vel  etiam 
2-5-septatis;  sporodochiis  minutis  vel  mediocribus  (usque  ad  2  mm.  diam.), 
saepe  in  pseudopionnotes  vergentibus;  aerio  mycelio  saepe  —  praecique  in 
agaribus  in  culturis  in  patellis  factis  —  absente;  conidiis  ex  albido  (in  aerio 
mycelio  similibus  magnis  granis  pulveris)  "dark  vinaceous  purple"  (R); 
vide  typicam  spororum  coloris  variationem,  Tab.  ii,  figg.  5,  6;  interdum 
in  tuberibus  Solani  tuberosi,  vel  unis  vel  paucis  sporodochiis  (2  mm.  diam.) 
nitide  "orange"  (R);  substrato  hyalino  vel  eodem  colore  quo  conidiorum 
moles;  interdum  sclerotiis  minutis  livido-atris  (^  mm.  diam.),  tum  demum 
eorundem  magnis  numeris  passim  in  substrato  in  tuberibus  Solani  tuberosi; 
zonatione  coloniae  vel  maxime  indistincta  vel  nulla  in  agaribus  neutralibus 
in  culturis  in  patellis  factis. 

Hab.  In  mollibus  vel  aridis  putridis  tuberibus  Solani  tuberosi,  Atlanta, 
New  York,  Amer.  bor. 

Measurements  of  spores  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  twenty-three  days  old; 

conidia  from  pseudopionnotes : 

Conidia:     0-septate,  4.5  per  cent,  9  x  2.7  (6-14  x  2.5-3)^1 
1-septate,  1  per  cent,  18  x  3.2  (13-22  x  2.6-4)^ 
2-septate,  0.5  per  cent,  19.5  x  3.2  (17-23  x  2.7-3.5) /i 
3-septate,  89  per  cent,  35.2  x  4.5  (23-38  x  3.5-4.7)m 
4-septate,  4.8  per  cent,  37.8  x  4.6  (31-40  x  4.3^.7)/i 
5-septate,  0.2  per  cent,  45  x  4.7  (38-50  x  4.7) /i 


FusARiA  OF  Potatoes  '  211 

On  red  raspberry  cane  plug,  culture  sixty  days  old;   conidia  from  a 

medium-sized  sporodochium : 

Conidia:     0-septate,  25  per  cent 
1-septate,  5  per  cent 
2-septate,  1  per  cent 

3-septate,  65  per  cent,  38  x  4.2  (27-44  x  3.5-4.7)/i 
4-septate,  4  per  cent,  42  x  4.4  (36-49  x  3.7-4.7) /x 
5-septate,  rare,  about  the  size  of  4-septate  conidia 

On  hard  lima-bean  agar,  culture  nine  days   old;   conidia  from  aerial 
mycelium : 
Conidia:     0-septate,  57  per  cent,  8.5  x  2.8  (7-12  x  2.6-3.5) /x 

1-septate,  16  per  cent,  14.5  x  3.25  (11-21  x  2.9-3.8) m 

2-septate,  3.5  per  cent 

3-septate,  23  per  cent,  28  x  3.9  (23-37  x  3.5-4.4) ^ 

4-septate,  0.5  per  cent,  35  x  3.9  (30-37  x  3.5-4.4) ^ 

On  same  media,  culture  twenty-two  days  old;  conidia  from  small  sporo- 

dochia : 

Conidia:  0-septate,  3  per  cent 
1-septate,  1  per  cent 
2-septate,  rare 

3-septate,  84  per  cent,  36  x  4  (29-40  x  3.9-4.4) ^ 
4-septate,  10  per  cent,  39  x  4.3  (33-42  x  3.9-4.7) ^ 
5-septate,  2  per  cent,  41  x  4.2/x  (only  a  few  measured) 

On  hard   potato   agar,   culture  thirty-one  days  old: 

(1)  Conidia   from  pseudopionnotes 

Conidia:     0-septate,  26  per  cent,  7.4  x  2.7  (5.2-12  x  2.6-3.5) /x 

1-septate,  4  per  cent,  13  x  3.3^  (only  three  measured) 
2-septate,  rare,  20  x  3.7/x  (only  three  measured) 
3-septate,  54  per  cent,  35  x  4.2  (20-41  x  3.4-4.8) ^ 
4-septate,  12  per  cent,  40  x  4.4  (35-44  x  4-4.8) /x 
5-septate,  4  per  cent,  43  x  4.8  (41-46  x  4-4.8) ^ 

(2)  Chlamydospores  (abundant) 

(a)  Terminal,  0-septate,  on  mycelium,  8  x  6.6  (7-9  x  6-7) ^t 

(b)  Intercalary,  in  mycelium 

0-septate,  8.2  x  6.2  (6-9  x  4.5-8) /x 
1-septate,  11  x  5.7/x  (only  a  few  measured) 

(c)  In  conidia,  0-septate,  6.5  x  5.9/x 


212  C.  D.  Sherbakoff 

On  potato  tuber  plug,  culture  ninety-nine  days  old: 

(1)  Conidia  from  a  sporodochium 

Conidia:     0-septate,  5  per  cent,  6.2  x  2.4  (4.5-8  x  2-2  9)/i 

1-septate,  1  per  cent,  13  x  2.1  n  (only  a  few  measured) 
2-septate,  rare,  20  x  3.3/i  (only  a  few  measured) 
3-septate,  92  per  cent,  32  x  3.8  (20-38  x  3-4.2)/i 
4-septate,  rare,  37  x  4.1^4  (only  one  measured) 
5-septate,  very  rare,  about  the  size  of  4-septate 

(2)  Chlamydospores,  numerous,  mostly  in  conidia 

0-septate,  6.8  x  5.1   (5.2-7.2  x  4.6-5.3) m 

1-septate,  9.6  x  5.1  (7.8-12.3  x  4.1-6)^,  the  largest  8.8  x  6.1// 

On  potato  stem  plug,  culture  one  hundred  and  twelve  days  old: 

(1)  Conidia  from  a  sporodochium 
Conidia:     0-septate,  1  per  cent 

1-septate,  rare 

3-septate,  79  per  cent,  36.4  x  4.1  (33-39  x  3.9-4.7)/: 
4-septate,  13  per  cent,  40  x  4.2  (36^2  x  3.9-4.4) /x 
5-septate,  7  per  cent,  40  x  4.3  (35-45  x  4-4.7) m 
6-septate,  very  rare,  same  size  as  5-septate 

(2)  Chlamydospores,  in  conidia  common,  mostly  0-septate,  6.3  x  5.2 

(5.1-8  X  4.3-6)  M 

On  whole  steamed  potato  tuber,  culture  forty-nine  days  old;  conidia 

from  a  sporodochium : 

Conidia :     0-septate,  4  per  cent 

3-septate,  86  per  cent,  36  x  3.7  (22^4  x  2.9-4.1)/i 
4-septate,  8  per  cent,  38  x  4.1  (35-43  x  3.9-4.2)/i 
5-septate,  2  per  cent,   40  x  4.1  (37-44  x  4.1)/i 

On  rye  grain,  culture  sixty-three  days  old;  conidia  from  a  small  sporo- 
dochium : 

Conidia:  0-septate,  35  per  cent 
1-septate,  12  per  cent 
2-septate,  1  per  cent 

3-septate,  45  per  cent,  34  x  4  (24-44  x  3. 5-4.4) m 
4-septate,  5  per  cent,  41  x  4.2  (36-47  x  4-4.7) /x 
5-septate,  2  per  cent,  45  x  4.3   (44-51,  x  4-4.7)  ju 


FusARiA  OF  Potatoes  213 

On  corn  agar,  culture  one  hundred  and  seventy-two  days  old;  most  of 
the  conidia  with  chlamydospores : 

(1)  Pseudopionnotal  conidia  (only  those  without  chlamydospores  were 

measured) 
Conidia:     3-septate,  32  x  4/i 
4-septate,  35  x4.1/t 
5-septate,  37  x  4.2ju 

(2)  Chlamydospores  in  conidia  very  numerous,  0-septate  predominant, 

7.3  X  6.8  (6-10  X  5-9) M 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  one  hundred 
and  eighteen  days  old : 

(1)  Chlamydospores  in  conidia  very  numerous,  0-septate  predominant, 

7.2x5.7  (6-8x5.2-6) At 

(2)  Sporodochial  conidia 

Conidia:     3-septate,  99  per  cent,  33  x  4.2  (29-39  x  3.8-4.7)m 

4-septate,  1  per  cent,  36  x  4.3  /x  (only  three  measured) 

On  hard  lima-bean  agar,  culture  five  days  old;  conidia  from  aerial  myce- 
lium (chlamydospores  in  conidia  not  observed) : 
Conidia:     0-septate,  46  per  (;ent,  about  11  x  2.6^ 

1-septate,  4  per  cent,  about  16x3.1^1 

2-septate,  1.5  per  cent 

3-septate,  48  per  cent,  32  x  4  (23^1  x  3.5-4.3) ^ 

4-septate,  0.5  per  cent,  35  x  4.1^*  (only  two  measured) 

On  same  medium  as  above,   culture  thirteen  days  old;  conidia  from 
aerial  mycelium: 
Conidia:     0-septate,  25  per  cent 

1-septate,  6  per  cent 

2-septate,  1  per  cent 

3-septate,  63  per  cent,  35  x  4.2  (30-40  x  3.9-4.7)/x 

4-septate,  5  per  cent,  37.8x4.4  (33^1x4^.7)m 
Average  of  the  above  measurements: 
Conidia:     0-septate,  20  per  cent  8.4  x  2.6/i 

1-septate,  1.5  per  cent,  15x3.2^1 

2-septate,  3.5  per  cent,  20  xSAfx, 

3-septate,  69  per  cent,  33.9  x  4.07 ju 

4-septate,  5  per  cent,  39.4  x  4.23/i 

5-septate,  1  per  cent,  41.1  x  4.32/* 


214  C  D.  Sherbakoff 

37.  Fusarium  lutulatum  var.  zonatum  n.  var.  (PL  i,  figs.  9  and  10; 
PI.  V,  fig.  4) 

Differs  from  F.  lutulatum  by  sfightly  shorter  and  broader  microconidia; 
usually  by  the  absence  of  chlamydospores  in  conidia;"*^  by  conidia 
somewhat  less  pointed  than  those  in  F.  lutulatum;  by  commoner  produc- 
tion of  aerial  mycelium;  and  by  more  or  less  distinct  zonation  of  colony 
growth  on  neutral  agars.  Spore  color  begins  to  develop  earher  but  usually 
does  not  reach  the  density  of  that  of  F.  lutulatum.  The  organism  does  not 
produce  rot  of  potato  tubers,  while  F.  lutulatum,  at  least  in  most  of  the 
inoculations  made,  is  capable  of  causing  such  rot.     No  sclerotia  observed. 

Hab.  On  rotted  tubers  of  Solarium  tuberosum  together  with  F.  oxy- 
sporum  var.  resupinatum  and  F.  sanguineum,  at  Ithaca,  New  York. 

The  size  of  the  conidia  is  in  many  instances  almost  identical  with  that 
in  F.  lutulatum,  and  in  general  there  is  scarcely  any  very  sharp  distinction 
between  the  two  organisms;  but  there  are  at  least  slight  differences  in 
many  of  the  important  characters,  so  that  in  general  there  can  hardly  be 
any  serious  doubt  that  these  are  two  distinct,  though  closely  related, 
organisms. 

Average  of  the  measurements  of  conidia  on  the  same  media,  of  the  same 
age,  and  the  same  in  other  ways,  as  those  of  F.  lutulatum,  is  as  follows : 

Conidia:    0-septate,  23  per  cent,  9  x  2.8/i 
1-septate,  5  per  cent,  16  x  3.1iu 
2-septate,  2  per  cent,  22  x  3.5At 
3-septate,  69  per  cent,  32.77  x  4.16)U 
4-septate,  1  per  cent,  39.4  x  4.4/x 
5-septate,  very  rare,  39.3  x  4.6m 

38.  Fusarium  sclerotioides  n.  sp.  (Figs,  loi  and  33;  PI.  i,  figs.  11  and  12; 
PI.  V,  fig.  1) 

Microconidia  gradually  attenuate  toward  and  more  or  less  pointed  at 
the  apex,  pedicellate,  generally  somewhat  more  distinctly  curved  near  apex, 
and  broader  in  the  middle  or  in  the  upper  third  of  their  .length,  typically 
3-septate,  34.7x4.4  (30-39.5  x  4.1-4.6)m,  also  2-  to  5-septate,  4-  and 
5-septate  being  of  more  or  less  common  occurrence;  chlamydospores 
observed  only  in  mycelium   (intercalary  and  terminal),   and  not  very 

*'  These  were  observed  in  number  only  once,  and  then  when  the  culture  was  very  old  and  much  con- 
taminated with  bacteria.  It  was  observed  generally  that  a  bacterial  contamination  greatly  stimulates 
production  of  chlamydospores. 


FusARiA  OF  Potatoes 


215 


common  nor  numerous  when  compared  with  all  the  other  species  of  sec- 
tion Elegans,  usually  only  unicellular;  aerial  mycelium  on  hard  agars 
invariably  well  developed,  of  medium  height  (from  2  to  4  millimeters) 
and  density,  very  frequently  forming  macroscopically  observable  knots  at 
the  hyphal  tips,  finally,  if  the  conditions  are  right,  resulting  in  production 
of  numerous  small  sporodochia;  large  (up  to  12  millimeters  in  diameter), 
bluish  black,  shiny,  more  or  less  wrinkled,  sclerotia  are  frequently  pro- 
duced on  potato  tuber  plugs;  the  sclerotia  in  some  cases  overgrown  with 
aerial  mycelium,  and  then  not  so  conspicuous;  plectenchymic  bodies 
(from  1  to  3  or  more  millimeters  in  diameter)   wartlike  in  appearance, 


Fig.  33. —  Fusarium  sclerotioides.  a,  Conidia  from  plectenchymic  sporodochium  from  14- 
days-old  culture  on  potato  tuher  plug;  b,  conidia  from  plectenchymic  sporodochium  from  58- 
days-old  culture  on  red  raspberry  cane  plug;  c,  conidia  from  24-days-old  culture  on  slightly 
acidified  hard  potato  agar;  d,  sporodochial  conidia  from  6-days-old  cidture,  e,  sporodochial 
conidia  from  12-days-old  cidture,  f,  sporodochial  conidia  from  51 -days-old  ctdture,  on  hard 
lima-bean  agar;  g,  microconidia  from  1 3-day s-old  culture  on  hard  lima-bean  agar  with  2  per 
cent  glucose;  h,  microconidia  from  aerial  mycelium,  i,  sporodochial  conidiophores,  from  58-days- 
old  culture  on  red  raspberry  cane  plug;  J,  conidiophore  from  6-days-old  culture  on  hard  lima- 
bean  agar;  k,  chlamydospores  from  58-days-old  culture  on  red  raspberry  cane  plug 


white  or  pale  flesh  in  color,  often  produced  in  considerable  number  and 
in  some  cases  finally  bearing  masses  of  septate  conidia;  conidia,  however, 
rarely  produced  on  the  sclerotia;  color  of  the  conidial  mass  somewhat 
variable,  but  usually  of  a  tint  of  pinkish  buff;  color  of  substratum  varying 
from  nearly  colorless  when  young  to  cinnamon  red,  deep  vinaceous,  and 
dark  vinaceous  purple.  (For  typical  color  when  mature  see  Plate  i, 
figure  12.) 


216  C.  D.  Sherbakoff 

Hab.  On  rotted  tubers  and  in  discolored  fibrovascular  bundles  of 
tubers  of  Solarium  tuberosum  at  Atlanta  and  Ithaca,  New  York,  and  in 
Louisiana. 

Cultures  of  this  organism  on  all  media  may  for  a  long  time  produce 
microconidia  almost  exclusively;  but  if  mature  macroconidia  from  oc- 
casionally produced  sporodochia  are  planted,  macroconidia  may  be  pro- 
duced again  in  new  cultures  in  great  abundance  and  on  almost  any  medium. 

Latin  description. — Microconidiis  gradatim  in  apicem  attenuatis,  apice 
acutis,  pedicellatis  plerumque  aliquatenus  distinctius  ad  apicem  curvatis, 
medio  latioribus  vel  superiore  tertio  longitudinis,  typice  3-septatis,  34.7 
x4.4  (30-39.5  X  4. 1-4.6) M,  vel  etiam  2-5-septatis,  plus  minusve  saepe 
4-5-septatis;  chlamydosporis  tantum  in  mycelio  (intercalaribus  et  ter- 
minalibus)  sed  nee  maxime  frequentibus  nee  multis  prae  ceteris  sectionis 
Elegantis  speciebus,  plerumque  tantum  unicellularibus;  aerio  mycelio  in 
duris  agaribus  semper  plene  maturo,  mediocriter  alto  (2-4  mm.)  densoque, 
saepissime  nodes  nudo  oculo  conspicuos  formante  in  hyphalibus  apicibus, 
demum  —  condicionibus  faventibus  —  multa  minuta  sporodochia  ferente; 
saepe  sclerotiis  magnis  (usque  ad  12  mm.  diam.)  livido-atris,  lucidis,  plus 
minusve  rugosis,  in  tuberibus  Solani  tuberosi;  sclerotiis  —  si  aerio  mycelio 
obsita  —  minus  conspicuis;  saepe  multis  plectenchymicis  corporibus 
(1-3  mm.  diam.,  vel  majoribus),  verrucoideis,  albis  vel  pallide  carneis,  vel 
moles  septatorum  conidiorum  vel  nullas  tandem  ferentibus;  conidiis  autem 
in  sclerotiis  raro  ortis;  colore  conidiorum  molis  aliquatenus  variante,  sed 
plerumque  "  pinkish  buff "  (R)  tincto;  colore  substrafi  juvenis  ferme  hyalino 
dein  "cinnamon  rufous"  (R)/'deep  vinaceous  "  (R)/'dark  vinaceous  purple" 
(R).     (Vide  typicam  colorem  maturi  substrati  Tab.  i,  fig.  12.) 

Hab.  In  putridis  tuberibus  et  in  decoloratis  fibro-vascularibus  fascicuhs 
tuberum  Solani  tuberosi,  Atlanta  et  Ithaca,  New  York,  et  Louisiana,  Amer. 
bor. 

Measurements  of  conidia  on  different  media  are  as  follows : 

On  red  raspberry  cane  plug,  culture  fifty-eight  days  old;  conidia  from  a 

sporodochium : 

Conidia:     1-septate,  1  per  cent 
2-septate,  1.5  per  cent 

3-septate,  87  per  cent,  30  x  4.4  (21-40  x  3-5. 1)^ 
4-septate,  9  per  cent,  37  x  4.5  (33-41  x  4.1-5.1)/i 
5-septate,  1.5  per  cent,  40  x  4.6  (35-45  x  4.3-5.1)/* 


FusARiA  OF  Potatoes  217 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  thirteen  days 
old ;  conidia  from  aerial  mycelium : 

Conidia:     0-septate,  90  per  cent,  9.5  x  2.25  (7-15.5  x  1.75-2.4)m 
1-septate,  10  per  cent,  13.4  x  2.5  (12-18  x  2.3-3)ju 

On  corn  meal  agar,  culture  one  hundred  and  seventy-three  days  old: 
Chlamydospores:     0-septate,  in  mycelium,  8.5  x  8.2  (7-11.5  x  5-10.5)/i 

On  hard  lima-bean  agar,  culture  six  days  old;  conidia  from  a  sporo- 

dochium : 

Conidia:     0-septate,  rare 

1-septate,  very  rare 

3-septate,  up  to  100  per  cent,  37  x  4.3  (31-41  x  3.9-4.4) /x 
4-septate,  rare,  37  x  4.4/i  (only  one  measured) 
On  same  medium  as  above,  culture  fifty-one  days  old;  conidia  from  a 

medium-sized  sporodochium : 

Conidia:  0-septate,  1  per  cent 
1-septate,  1.5  per  cent 

3-septate,  73  per  cent,  33  x  4.5  (23-39  x  3.5-4.8))li 
4-septate,  23  per  cent,  37  x  4.5  (31-42  x  4^.8)/x 
5-septate,  1.5  per  cent,  38  x  4.6  (31-42  x  4.2^.9)/i 

On  same  medium  as  above,   culture  twelve  days  old;   conidia  from 

pseudopionnotes : 

Conidia:  0-septate,  6  per  cent 
1-septate,  3  per  cent 
2-septate,  exceptional 

3-septate,  74  per  cent,  35  x  4.6  [(22-)  33-39  x  (3.5-)  4.1-4.8]/x 
4-septate,  16  per  cent,  36  x  4.7  (33-42  x  4.4-4.8) ^ 
5-septate,  1  per  cent,  37  x  4.7  (35-40  x  4.6-4.8) m 

On  potato  tuber  plug,  culture  fourteen  days  old;  conidia  from  a  medium- 
sized  sporodochium : 
Conidia:    0-septate,  8  per  cent 
1-septate,  3  per  cent 
2-septate,  rare 

3-septate,  46  per  cent,  35  x  4.1  (29^3  x  3-4.7) ju 
4-septate,  29  per  cent,  40  x  4.2  (31^7  x  3.5-4.7) /z 
5-septate,  14  per  cent,  40  x  4.3  (35-47  x  4-4.7) m 


218 


C.  D.  Sherbakoff 


On  hard  oat  agar,  culture  twenty-four  days  old;  conidia  from  a  sporo- 

dochium : 

Conidia:     3-septate,  64  per  cent,  39.5  x  4.3  (36-52  x  4-4.7) m 
4-septate,  28  per  cent,  41  x  4.3  (38-45  x  4-4.7)  m 
5-septate,  8  per  cent,  43  x  4.5  (38-46  x  4.1^.7)/* 

Average  of  the  above  measurements : 
Conidia:     0-septate,  16  per  cent,  9.5  x  2.25/* 
1-septate,  3  per  cent,  13.4  x  2.5/x 
2-septate,  rare 

3-septate,  63  per  cent,  34.7  x  4.4/t 
4-septate,  15  per  cent,  37.9  x  4.43/* 
5-septate,  3  per  cent,  39.35  x  4.55ju 


Fig.  34. —  Fusarium  sclerotioides  var.  hrevius.  a,  Pseudopionnotal  conidia  from  8-days- 
old  culture  on  hard  lima-bean  agar;  b,  sporodochial  conidia,  c,  conidia  from  aerial  mycelium, 
from  19-days-old  culture  on  slightly  acidified  hard  potato  agar;  d,  sporodochial  conidia  from 
^5-days-old  culture  on  red  raspberry  cane  plug;  e,  conidia  from  aerial  mycelium  from  13-days- 
old  culture  on  hard  lima-bean  agar  with  2  per  cent  glucose;  f,  sporodochial  conidia,  g,  aerial 
conidia,  from  60-days-old  culture  on  whole  steamed  potato  tuber;  h,  sporodochial  conidia  from 
35-days-old  culture  on  oats;  i,  chlamydospores  from  J^S-days-old  culture  on  red  raspberry  cane 
plug;  i,  chlamydospores  from  25-days-old  culture  on  corn  agar;  k,  l,  conidiophores  from  19- 
days-old  cidture  on  slightly  acidified  hard  potato  agar;  m,  swollen  tips  of  aerial  hyphce  from 
1 3-day s-old  culture  on  hard  lima-bean  agar  with  2  per  cent  glucose 


39.  Fusarium  sclerotioides  var.  brevius  n.  var.  (Fig.  34;  PI.  ii,  figs.  1 
and  2) 

Differs  from  F.  sclerotioides  mainly  by  nearly  constant  absence  of  4- 
and  5-septate  conidia,  by  absence  of  large  bluish  black  sclerotia,  and  by 
noticeably  shorter,  3-septate  conidia. 

Hab.  In  discolored  fibrovascular  bundles  of  tubers  of  Solarium  tube- 
rosum, Alabama. 

Measurements  of  the  conidia  on  different  media  are  as  follows: 


FusARiA  OF  Potatoes  219 

On  red  raspberry  cane  plug,  culture  forty-five  days  old;  conidia  from 

a  plectenchymic  sporodochium : 

Conidia:     0-septate,  8  per  cent,  15  x  3  (6-21  x  2.5-3.5) /x 

1-septate,  17  per  cent,  18  x  3.7  (17-23  x  3.5-4)ai 
2-septate,  15  per  cent,  20  x  4  (17-23  x  3.5-4.4)/x 
3-septate,  60  per  cent,  28.3  x  4.3  (19-39  x  3.5-4.8)/i 
4-septate,  rare 

On  slightly  acidified  hard  potato  agar,  culture  nineteen  days  old;  conidia 

from  a  small  sporodochium : 

Conidia:     0-septate,  rare 
1-septate,  rare 

2-septate,  2  per  cent,  24  x  4.2  (20-27  x  3.5-4.7)m 
3-septate,  98  per  cent,  30.3  x  4.5  (21-37  x  4.1-4.8)m 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  thirteen  days 
old ;  conidia  from  aerial  mycelium : 

Conidia:     0-septate,  98  per  cent,  7.5  x  2.6  (4.3-18  x  2.3-3.7) /x 
1-septate,  2  per  cent,  13.5  x  3.2  (10-18  x  2.4-3.5) m 

On  same  medium  as  above,  culture  sixty-five  days  old;  conidia  from  a 

sporodochium : 

Conidia:     0-septate,  8  per  cent,  6.4  x  2.8  (4.4-11  x  2.3-4.1)/* 
1-septate,  5  per  cent,  22  x  3.8  (15-29  x  3-4.3) m 
2-septate,  2  per  cent,  24  x  4  (18-28  x  3.5-4.4) /x 
3-septate,  85  per  cent,  28  x  4.3  (24-35  x  3.7-4.8)  m 

On  corn  meal  agar,  culture  one  hundred  and  seventy-three  days  old: 
Chlamydospores :     0-septate,  in  conidia,  7.9  x  7  (5-11.5  x  5-9) m 

1-septate,  in  mycelium,  13.3  x  8.1  (11-18  x  7-9) /i 

On  hard  lima-bean  agar,   culture  eight  days  old;  conidia  from  aerial 
mycelium : 
Conidia:     0-septate,  55.5  per  cent,  7.8  x  2.8  (5.2-13  x  2. 1-3.9) /x 

1-septate,  4  per  cent,  13.3  x  3.2  (12-15  x  3-3.6) /x 

2-septate,  0.5  per  cent 

3-septate,  40  per  cent,  30.8  x  4.1  (23-37  x  3.9-4.2)m 


220  C.  D.  Sherbakoff 

On  same  medium  as  above,   culture  twelve  days  old;   conidia  from 
pseudopiomiotes : 
Conidia:     0-septate,  12  per  cent 

1-septate,  3  per  cent 

2-septate,  2  per  cent 

3-septate,  83  per  cent,  31  x  4.3  (22^1  x  4-4.7)  m 

4-septate,  exceptional,  41  x  4.4^t  (only  one  measured) 

On  hard  oat  agar,  culture  twenty-four  days  old;  conidia  from  a  sporo- 
dochium : 

3-septate,  100  per  cent,  31.5  x  4.4  (23-35  x  3.8-4.7)m 

Average  of  the  above  measurements: 
Conidia:     0-septate,  30.5  per  cent,  9.2x2.8/* 
1-septate,  5  per  cent,  16.5  x  3.5/i 
2-septate,  3.5  per  cent,  22  x  4/* 
3-septate,  61  per  cent,  29.8  x  4.3jli 
4-septate,  very  rare,  41  x  4.4/* 

40.  Fusarium  oxysporum  Schlecht.^^     (Figs.  1ni  and  35a;  PI.  v,  fig.  6) 
Schlechtendal,   Fl.  Berol.,  2:139.   1824.     Smith,  E.   F.,  and  Swingle, 
D.  B.,  U.  S.  Plant  Indus.  Bur.,  Bui.     55.  1904.     Wollenweber,  H.  W., 
Phytopath.  3:28,  fig.  If.     1913.     Wollenweber,  H.  W.,  Journ.    Agr.  Re- 
search 2:268.     1914. 

Microconidia  gradually  pointed  toward  apex,  nearly  cylindrical  in  middle 
half  of  their  length,  typically  not  broader  toward  apex,  usually  somewhat 
distinctly  pedicellate,  3-septate  dominant,  30.4x4.2  (27.5-34  x 4-4.4) /i,^^ 
in  sporodochia  and  pseudopiomiotes;  4-septate  macroconidia  frequently, 
and  5-septate  ones  rarely,  present;  in  mass  usually  of  pinkish  buff  color; 
aerial  mycelium  typically  well  developed,  of  medium  height  (from  3  to  5 
millimeters)  and  density,  from  white  to  (in  spots  on  boiled  rice)  congopink; 

^8  Original  description  of  F.  oxysporum  Schlecht.  (see  von  Schlechtendal,  Flora  Berolinensis  2  :  139)  — 
"  t'  stroma  convexum  erumpens  varium  roseiim  superficie  inaequali  rugulosa,  sporidiis  parvis  curvatis 
utrinque  acutissimis  " —  is  insufficient  for  identification  of  the  species,  and,  short  as  it  is,  it  sooner  suggests 
some  other  species  and  not  that  of  Smith  and  Swingle.  For  a  detailed  discussion  of  the  matter  see  Appel 
and  Wollenweber  (1910:  144-146). 

Wollenweber  (1913  a :  28)  gives  his  own  description  of  F.  oxysporum  Schlecht.,  which,  as  he  states  (page  42 
of  reference  cited),  "  includes  some  additions  to  the  descriptions  given  by  Smith  and  Swingle." 

For  the  reason  that,  at  least  among  pathologists  and  mycologists  of  the  United  States,  this  organism 
is  fairly  well  known  under  this  name,  and  after  Wollenweber's  description  of  it  the  meaning  became 
definite  and  recognizable,  the  name  F.  oxysporum  is  retained  here  and  is  used  for  the  organism  described 
by  Wollenweber  without  consideration  of  Schlechtendal's  original  description;  that  is,  F.  oxysporum  here 
is  as  emended  by  Wollenweber. 

"Wollenweber  (1913  a:  28)  gives  the  size  variation  as  25-45x3.25-4.5/1.  Whether  this  is  average 
or  individual  size  variation  is  not  stated. 


FusARiA  OF  Potatoes 


221 


substratum,  on  potato  agar  rich  in  glucose, 
colorless  and  orange  vinaceous  to  pome- 
granate purple  and  vinaceous  purple; 
plectenchymic  sporodochia  common  on 
most  of  the  media;  bluish  black  sclerotia 
(up  to  3  millimeters  in  diameter)  con- 
stantly present  on  potato  tuber  plug  and 
sometimes  on  different  agars. 

Hab.  In  fibrovascular  bundles  of 
diseased  stems  and  tubers  of  Solanum 
tuberosum,  in  the  United  States,  perhaps 
also  in  Europe,  Africa,  and  other  regions, 
also  on  Lycopersicum  esculentum  Vigna, 
and  Pisum. 

The  organism  was  isolated  alone  and  in 
association  with  several  other  Fusaria, 
several  times  from  various  localities  in 
New  York  and  in  other  States.  The  de- 
scription given  above  is  based  on  the  study 
of  the  culture  obtained  through  the  cour- 
tesy of  Dr.  Wollenweber. 

Measurements  of  the  conidia  are  as 
follows : 

On  slightly  acidified  hard  potato  agar, 
culture  nineteen  days  old;  conidia  from 
aerial  mycelium  close  to  substratum: 


vinaceous  lilac,  varying  from 


Fig.  35. —  a,  Fusarimn  oxysporum, 
sporodochial  conidia 

B-J,  F.  oxysporuni  var.  asclerotium: 
B,  Conidia  from  IJ^-days-old  culture 
on  slightly  acidified  hard  potato  agar; 
c,  conidia  from  J^d-days-old  culture 
on  red  raspberry  cane  plug;  d,  conidia 
from  7-days-old  culture  on  hard 
lima-bean  agar;  e,  chlamydospores 
from  46-days-old  culture  on  red 
raspberry  cane  plug;  f,  terminal 
chlamydospores  produced  on  normal 
conidiophore^,  a  and  h,  conidio- 
phores  (h  magnified  250  times)  from 
14-days-old  ctdture  on  slightly  acidi- 
fied hard  potato  agar;  i,  chlamydo- 
spores from  25-days-old  culture  on 
corn  agar;  j,  conidiophores  from 
7-days-old  cidture  on  hard  lima-bean 
agar 


Conidia:     0-septate,  87  per  cent,  8x2.9  (4.5-12  x  2-4) ^u 

1-septate,  6  per  cent,  16.5x3.4  (11-23  x  2.5-4. 1)/^ 
2-septate,  1  per  cent,  18.5  x  3.9  (17-26  x  3-4.2)/x 
3-septate,  5  per  cent,  27.5  x  4  (15-39  x  3^.7)  m 
4-septate,  1  per  cent,  about  40x4.5  (36-44  x  4.3-4.8) /x 

On  hard  lima-bean  agar,  culture  twelve  days  old;  conidia  from  aerial 
mycelium : 

Conidia:     0-septate,  99  per  cent,  6.5  x  2.6  (4.5-16  x  1.75-3.5) /x 
1-septate,  1  per  cent,  14  x  3.2  (10-17  x  3-3.5) /x 


222  C.  D.  Sherbakoff 

On  same  medium  as  above,  culture  sixty-five  days  old: 

(1)  Conidia  from  a  sporodochium 
Conidia:     0-septate,  3  per  cent 

1-septate,  1  per  cent 

3-septate,  93  per  cent,  33.8  x  4.3  (22-42  x  4-4.7) m 
4-septate,  3  per  cent,  35.7  x  4.3  (33-41  x  4.1-4.7)m 
5-septate,  rare,  35  x  4.4/x  (only  two  measured) 

(2)  Chlamydospores,  terminal  and  intercalary,  0-septate  dominant 
Chlamydospores:    0-septate,  8.7  x  8  (7-12.5  x  7-12.5) /x 

1-septate,  15.5  x  9.2  (12-22  x  7.7-14) /x 

Also    in    short    chain,    2-  and  3-septate,  2-septate 
commoner 

On  hard  oat  agar,  culture  twenty-three  days  old;  conidia  from  a  sporo- 
dochium : 

Conidia:     3-septate,  93  per  cent,  30  x  4.4  (26-35  x  3.9-4.7) m 
4-septate,  6  per  cent,  34.5  x  4.5  (31-39  x  4.2-4.7)m 
5-septate,  1  per  cent 

On  corn  meal  agar,  culture  one  hundred  and  seventy-three  days  old; 
chlamydospores  abundant,  terminal  and  intercalary : 
Chlamydospores:     0-septate,  in  conidia,  7.2  x  6.1  (6-9  x  4.8-8) /x 

0-septate,  in  mycelium,  8.6  x  8  (7-10  x  7-11)/* 

1-septate,  often  observed 

On  hard  lima-bean  agar,  culture  fifty  days  old;  chlamydospores  inter- 
calary and  terminal,  in  conidia  and  in  mycelium,  the  latter  most  commonly 
observed : 
Chlamydospores:     0-septate  dominant,  8.9x7.3  (5.2-11  x  5.2-1  l)/i 

Average  of  the  above  measurements  of  macroconidia : 
Conidia:    3-septate,  0-93  per  cent,  30.4  x  4.2/i 

4-septate,  0-6  per  cent,  36.7x4.43  (34.5-60  x  4.3-4.5)  m 
5-septate,  0-rare,  about  35  x  4.4/i 

41.  Fusarium  oxijsporum  Schlecht.  var.  asclerotium  n.  var.  (Fig.  35,  b  to  j; 
PI.  V,  fig.  7) 

Differs  from  F.  oxysporum  mainly  by  absence  of  sclerotia  and  of  defi- 
nite plectenchymic  sporodochia;  differs  also  in  color  of  mycelium  and  in 
somewhat  longer  and  narrower  macroconidia. 

Hab.     In  rotted  tuber  of  Solarium  tuberosum,  Atlanta,  New  York. 


FusARiA  OF  Potatoes 


223 


The  organism  was  isolated  from  a  flexible,  semi-soft,  rotted  potato 
tuber  late  in  the  spring.  No  other  organisms  were  associated  with  it. 
Very  similar  organisms  were  isolated  also  from  discolored  fibrovascular 
bundles  of  potato  tubers  from  various  States. 

Average  measurements  of  the  conidia  from  four  different  cultures  are  as 
follows: 

Conidia:     0-septate,  52.5  per  cent,  7.9  x  2.6/1 
1-septate,  8  per  cent,  15  x  3.1^t 
2-septate,  rare 

3-septate,  39  per  cent,  34  x  4  (32-36  x  3.8-4.2) m^" 
4-septate,  0.5  per  cent,  37.5  x  4.35/1 
5-septate,  very  rare,  37.5  x  4.35/i 

Chlamydospores  (on  corn  meal  culture  one  hundred  and  seventy-three 
days  old) : 

0-septate,  in  conidia,  7.7  x  7  (6.5-11  x  5-8) /t 
0-septate,  in  mycelium,  9x8  (7-11  x  5-8) /i 
1-septate,  in  mycelium,  14  x  9.5  (11-16.5  x  7-13.4) /i" 


Fig.  36. —  Fusarium  oxysporuni  var.  longius.  a,  Pseudopionnotal  conidia  from  21-days-old 
culture  on  slightly  acidified  hard  potato  agar;  b,  conidia  from  46-days-old  culture  on  red  rasp- 
berry cane  plug;  c,  pseudepionnotal  conidia  from  5-days-old  hard  lima-bean  agar;  d,  sporo- 
dochial  conidia  from  36 -days-old  culture  on  oat  agar;  e,  pseudopionnotal  conidia  from  22-day s- 
old  culture  on  corn  agar;  f,  conidia  from  202-days-old  culture  on  potato  stem  plug;  g,  conidio- 
phores  from  46-days-old  culture  on  red  raspberry  cane  plug;  h,  conidiophores  from  5-days-old 
culture  on  hard  lima-hean  agar;  i,  chlamydospores  from  202-days-old  culture  on  potato  stem 
plug 

*"  Variation  of  averages  of  at  least  ten  spore  moasuremeDts. 
*i  Variation  of  individual  spore  measurements. 


224  C.  D.  Sherbakoff 

42.  Fusarium  oxysporum  Schlecht.  var.  longius  n.  var,  (Figs.  1mi  and  36) 
Differs  from  F.  oxysporum  and  other  varieties  of  the  species  by  longer 
macroconidia,  typically  3-septate,  38.94x4.04  (34-45  x  3.6-4.4) m,  often 
4-  and  5-septate;  no  sclerotia;  no  macroscopical  sporodochia. 

Hab.  In  discolored  fibrovascular  bundles  of  tubers  of  Solarium  tube- 
rosum and  of  wilted  stems,  in  New  York,  California,  Maryland,  and 
Connecticut. 

On  shghtly  acidified  hard  potato  agar,  culture  twenty-one  days  old: 

(1)  Conidia  from  pseudopionnotes 

Conidia:    0-septate,  1.5  per  cent,  10  x  3  (8-12  x  2.5-3.5)/t 
1-septate,  3  per  cent,  18  x  3.5  (14-21  x  3-4) ac 
2-septate,  0.5  per  cent 

3-septate,  60  per  cent,  42.7  x  4.1  (28-54  x  3.5-4.8)  m 
4-septate,  26  per  cent,  49  x  4.3  (42-58  x  4-^.8) /x 
5-septate,  9  per  cent,  51.4  x  4.6  (46-60  x  4.3-4.7)m 

(2)  Chlamydospores,  terminal  and  intercalary 
Chlamydospores :     0-septate,  7-9  x  5-6^ 

On  red  raspberry  cane  plug,  culture  forty-six  days  old;  conidia  from 
mycelium  close  to  substratum: 
Conidia:    0-septate,  1.7  per  cent,  11  x  2.6/i 

1-septate,  1  per  cent,  19  x  3jit 

2-septate,  rare 

3-septate,  93  per  cent,  34  x  4.4  (19^4  x  3.5-5.7)ju 

4-septate,  4.3  per  cent,  40  x  4.6  (35^4  x  4.2-4.8) /x 

On  corn  meal  agar,  culture  twenty-two  days  old;  conidia  from  surface 
of  medium: 
Conidia:    0-septate,  20  per  cent 

1-septate,  8  per  cent 

2-septate,  2  per  cent 

3-septate,  40  per  cent,  45  x  3.6  (36-54  x  3.2-4.2)/* 

4-septate,  20  per  centl  +v.    i         +  py     4 

5-septate,  10  per  cent/ 


FusARiA  OF  Potatoes  225 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  thirteen  days 

old;  conidia  from  aerial  mycelium: 

Conidia:     0-septate,  50  per  cent,  8.6  x  2.5  (5.2-15  x  2.2-3)  m 

1-septate,  10  per  cent,  17.5  x  2.9  (12-21  x  2.3-3.5) /x 
2-septate,  0.5  per  cent,  21  x  3.2)u    (only  three  measured) 
3-septate,  30  per  cent,  35.6  x  4  (24-50  x  3.2-4.4)^ 
4-septate,  8  per  cent,  45  x  4.2  (40-51  x  3.9-4.7)/x 
5-septate,  1.5  per  cent,  47.5  x  4.3  (42-51  x  3.9-5.1)^ 

On  hard  lima-bean  agar,   culture  five  days  old;  conidia  from  aerial 

mycelium : 

Conidia:     0-septate,  56  per  cent,  11  x  2.4/i  (only  four  measured) 
1-septate,  4  per  cent,  18  x  3.3^  (only  four  measured) 
2-septate,  1.5  per  cent 

3-septate,  37  per  cent,  37  x  4  (26^7  x  3.8-4.4) ju 
4-septate,  1  per  cent,  43  x  4.3  (40-45  x  4-4.5) /x 
5-septate,  0.5  per  cent,  50  x  4.4^t    (only  three  measured) 

On  corn  meal  agar,  culture  one  hundred  and  seventy-three  days  old: 
Chlamydospores:     (1)  0-septate,  in  conidia,  8.4  x  6.8  (7-9  x  5-8)  ^u 

(2)  0-septate,  terminal,  on  mycelium,   10  x  9  (9-10.5 
X  7.5-10.5)m 

On  potato  stem  plug,  culture  two  hundred  and  two  days  old: 

(1)  Conidia  from  aerial  mycelium  close  to  substratum 
Conidia:     0-septate,  40  per  cent 

1-septate,  20  per  cent 
2-septate,  10  per  cent 
3-septate,  30  per  cent,  34.3  x  3.9  (22-^2  x  3.4-4.1)^ 

(2)  Chlamydospores,  terminal  and  intercalary,  in  spores  and  mycelium 
Chlamydospores:     0-septate,  8.9  x  6.8  (6.2-10  x  5.2-9) m 

On  hard  lima-bean  agar,  culture  twelve  days  old;  conidia  from  pseudo- 
pionnotes : 
Conidia:     0-septate,  2  per  cent 

1-septate,  1  per  cent 

2-septate,  rare 

3-septate,  70  per  cent,  44  x  4.3  (35-48  x  4-4.8)/* 

4-septate,  23  per  cent 

5-septate,  4  per  cent,  46  x  4.3  (40-53  x  4.1-5.2)iu 


226 


CD.  Sherbakoff 


*     On  hard  oat  agar,  culture  fourteen  days  old;  conidia  from  pseudopion- 

notes : 

Conidia:     0-septate,  4  per  cent,  10  x  2.5/i 
1-septate,  1  per  cent 
2-septate,  rare 

3-septate,  70  per  cent,  44  x  4.04  (39-50  x  3.5-4.7) /x 
4-septate,  20  per  cent,  45  x  4.2  (41-50  x  4-4.7) m 
5-septate,  5  per  cent,  49  x  4.46  (42-51  x  4.3^.7)  m 

Average  of  the  above  measurements: 
Conidia:     0-septate,  24  per  cent,  10  x  2.6/i 
1-septate,  7  per  cent,  17.5  x  3.2/* 
2-septate,  1  per  cent,  21  x  3.2/x 
3-septate,  52  per  cent,  38.94  x  4.04/1 
4-septate,  12  per  cent,  44.25  x  4.35/* 
5-septate,  4  per  cent,  48.7  x  4.4/x 


Fig.  37. —  Fusarium  oxyspormn  var.  reswpinatum.  a,  Pseudopionnotal  conidia  from  15- 
days-old  culture  on  slightly  acidified  hard  potato  agar;  b,  conidiophores  from  6-days-old  culture 
on  hard  lima-bean  agar;  c,  conidiophore  from  1 2-day s-old  culture  on  hard  lima-bean  agar; 
D,  pseudopionnotal  conidia  from  6-days-old  culture  on  hard  lima-bean  agar;  e,  conidiophores 
and  chlamy  do  spores,  f,  conidia,  from  Ji.7 -days-old  culture  on  red  raspberry  cane  plug 


43.  Fusarium  oxysporum  Schlecht.  var.  resupinatum  n.  var.  (Figs. 
iLi   and  37;  PI.  i,  figs.  7  and  8;  PI.  v,  fig.  5) 

Differs  from  F.  oxysporum  by  absence  of  sclerotia,  from  var.  asclerotium 
and  var.  longius  by  shorter  and  somewhat  narrower  macroconidia. 
Mycelium  on  different  agars  typically  entirely  resupinate  (PI.  i,  figs.  7 
and  8). 


FusARiA  OF  Potatoes  227 

Hab.  In  discolored  fibrovascular  bundles  of  stem  and  tubers  of  Solanum 
tuberosum,  United  States. 

This  fungus  and  F.  oxysporu7n  var.  longius  are  the  organisms  that 
were  found  very  commonly  present  in  discolored  fibrovascular  bundles 
of  potato  tubers  and  wilted  plants.  These  organisms  are  also,  as  it  seems, 
most  commonly  recognized  by  various  pathologists  as  F.  oxyspomm 
Schlecht.,  as  described  by  Smith  and  Swingle  (1904);  at  least  cultures 
of  organisms  undoubtedly  belonging  here  were  received  under  the  name 
F.  oxysporum  from  Mr.  Wight  in  California,  Dr.  Taubenhaus  in  Delaware, 
and  Dr.  Clinton  in  Connecticut.  The  chief  difference  between  these 
varieties  of  F.  oxysporum  of  Smith  and  Swingle  lies  in  the  absence  of  sclerotia. 

Measurements  of  spores  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  fifteen  days  old;  conidia 

from  thin  pseudopionnotes : 

Conidia:     0-septate,  74  per  cent,  8x2.7  (5-15  x  2-4.3) )U 
1-septate,  9  per  cent,  21  x  3  (12-27  x  2.3-4.8) /z 
2-septate,  4  per  cent,  26  x  3  (20-37  x  2.2^.1)/i 
3-septate,  13  per  cent,  35  x  4.2  (22-57  x  S.5-A.7) fi 
4-septate,  rare,  45  x  4.2/x 

On  red  raspberry  cane  plug,  culture  forty-seven  days  old;  conidia  from 
aerial  mycelium: 
Conidia:     0-septate,  98  per  cent,  6.5x2.7  (4.5-21  x  2.3-4.3) ^ 

1-septate,  2  per  cent,  18x3.2  (12-24  x  2.8-4.  1)ai 

2-septate,  rare,  22  x  3.4  (17-24  x  3^.1)/i 

3-septate,  rare,  29  x  3.6  (19-36  x  3-4) /x 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  fifteen  days  old; 
conidia  from  aerial  mycelium: 
Conidia:     0-septate,  97  per  cent,  7.1  x  2.6  (5.2-16  x  1.8-4.3)/! 

1-septate,  2  per  cent,  16  x  3.1  (10-18  x  2.3-3.8)ai 

2-septate,  0.5  per  cent 

3-septate,  0.5  per  cent,  28x3.5  (23-36  x  2.4-4) /x 

On  corn  meal  agar,  culture  one  hundred  and  seventy-three  days  old: 
Chlamydospores :    0-septate,  in  conidia,  7.2  x  7  (5.8-9  x  5-8) /t 

0-septate,  in  mycehum,  9.6  x  8.3  (7-16  x  7-11.5)At 
1-septate,  in  mycelium,  14.5x9.2  (13-18x7-11)/* 


228  C  D.  Sherbakoff 

On  hard  lima-bean  agar,  culture  six  days  old;  conidia  from  pseudo- 
pionnotes : 
Conidia:     0-septate,  82  per  cent 

1-septate,  5  per  cent 

2-septate,  2  per  cent 

3-septate,  11  per  cent,  28  x  4.1  (22-36  x  3.9-4.7) m 

On  the  same  medium  as  above,  culture  twelve  days  old;  conidia  also 
from  pseudopionnotes ; 
Conidia:     0-septate,  15  per  cent 
1-septate,  8  per  cent 

3-septate,  77  per  cent,  33.5  x  4.1  (29-37  x  4-4.5) m;  the  smallest 
21  X  3.4/x,  the  largest  40  x  4.5^1  (both  3-septate) 

Chlamydospores  all  kinds  except  terminal,  0-septate  dominant,  measur- 
ing 8.3  X  6.7  (6-10.5  x  5.2-8)m 

Average  of  the  above  measurements: 
Conidia:     0-septate,  73  per  cent,  7.2  x  2.7/x 
1-septate,  5  per  cent,  18x3.1/i 
2-septate,  1.5  per  cent,  24  x  3.2^ 
3-septate,  20.5  per  cent,  30.7  x  3.9/x 
4-septate,  rare,  45  x  4.2^ 

X.  Section  Discolor  Wr.,  Phytopath.  3:31,  fig.  1,  g,  h,  j,  1913 
Conidia  sickle-shaped,  at  the  middle  nearly  cylindrical  or  broadened 
toward  the  apex,  somewhat  abruptly  apically  attenuated,  distinctly 
pedicellate;  mostly  3-  to  5-septate,  5-septate  dominant;  microconidia 
typically  absent;  chlamydospores  intercalary  only,  usually  scant;  mycelium 
typically  well  developed,  with  from  nearly  white  to  orange  color  as  type. 
Substratum  from  nearly  colorless  to  chamois,  pomegranate  purple,  and 
spectrum  red.  Color  of  conidia  very  variable,  mostly  cinnamon  to  orange. 
Differs  from  sections  Elegans  and  Martiella  by  absence  of  microconidia, 
by  the  conidia  being  typically  somewhat  abruptly  attenuate,  by  absence 
of  terminal  chlamydospores,  and  by  absence  of  vinaceous,  drab-gray, 
tawny-olive,  and  blue  color  of  substratum.  By  the  shape  of  conidia 
this  S3ction  occupies  an  intermediate  position  between  sections  Elegans 
and  Martiella;  by  its  color  it  is  closely  related  to  sections  Roseum  and 
Ferruginosum. 


FusARiA  OF  Potatoes 


229 


(Figs    1,  Ui  and  Vi,  and  38;  PI.   iv, 
H.  W.,  Journ.  Washington  Acad. 


44.  Fusarium  trichothecioides  Wr 
fig.  8) 

Jamieson,  CO.,  and  Wollenweber. 

Sci.  2:146-152,  fig.  1.     1912. 

Syn.     Fusarium  tuberivorum  "Wilcox  and  Link,  Nebraska  Agr.  Exp.  Sta.,  Research  bul 
1  :  48.     1913. 

Conidia  of  comma  and  discolor 
types  the  former  predominating 
and  under  ordinary  cultural  con- 
ditions occurring  almost  exclu- 
sively, mostly  1-septate,  16  x  4.6 
(14-17  X  4.2-5.4) Ai,  often  0-  to 
3-septate,  seldom  4-  or  5-septate, 
6-septate  rare;  sporodochial  co- 
nidia sickle-shaped,  3-  to  5-sep- 
tate, 24-42  X  4.5-5.5^.'^-  Typical 
conidiopho  es  of  comma  stage 
shown  in  figure  38.  Sporodochial 
conidiophores  similar  to  those  of  F. 
discolor.  F.  trichothecioides  can  be 
recognized  at  once  by  color  and 
appearance  of  its  powdery  masses 
of  spores  produced  on  aerial  myce- 
lium (PI.  IV,  fig.  8).  Chlamydo- 
spores  few  and  not  prominent. 

Hab.  On  rotted  tubers  of  So- 
larium tuberosum,  United  States. 

This  species  is  noticeably  dif- 
ferent from  all  other  species  of  the 
section  Discolor.  It  is  listed 
under  this  section  chiefly  because 
of  its  resemblance  in  the  sporodochial  form 
the  type  of  a  new  section. 

The  organism,  under  the  name  F.  tuberivorum  Wilcox  and  Link,  was 


Fig.  3S. —  Fusarium  trichothecioides.  a,  Conidia 
from  41 -days-old  culture  [on  rye  straw;  b, 
conidia  from  70-days-old  cidture  on  potato 
stem  plug;  c,  conidia  from  73-days-old  cidture 
on  red  raspberry  cane  plug;  d,  conidia  from 
15-days-old  culture  on  slightly  acidified  hard 
potato  agar;  e,  chlamydospore  in  conidium 
from  73-days-old  culture  on  red  raspberry 
cane  plug;  f,  conidiophores  (magnified  250 
times)  from  70-days-old  cidture  on  potato  stem 
plug;  6,  conidiophores  from  15-days-old  culture 
on  slightly  acidified  hard  potato  agar;  H, 
conidia  from  5-days-old  culture  on  hard  lima- 
bean  agar;  i,  comma,  J,  discolor,  type  of  co- 
nidia from  5-days-old  culture  on  potato  tiber 
plug 


Perhaps  it  should  be  made 


5-  The  size  of  3-  to  5-septate  conidia  is  as  given  by  Wollenweber.  The  writer  isolated  this  Fusarium 
from  specimen-s  of  rotted  potato  tubers  received  from  North  Dakota  in  July,  1912,  and  from  Texas  in 
December,  1913.  No  special  study  of  this  organism  was  made  at  first,  because  it  is  easily  recognizable 
even  after  a  superficial  examination,  and  also  because  its  description  as  given  by  Wollenweber  (see  Je 
and  Wollenweber,  1912)  is  entirely  sufficient  for  its  identification. 


230  C.  D.  Sherbakoff 

extensively  studied  by  Wilcox,  Link,  and  Pool  (1913).     The  identity  of 

F.  tuherivorum  and  F.  trichothecioides  Wr.  is  discussed  by  Wollenweber 

(1913  c :  206).     In  the  writer's  opinion  there  is  no  doubt  that  this  is  correct. 

The  few  measurements  of  the  conidia  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  fifteen  days  old: 
Conidia:     0-septate,  23  per  cent,  8.2  x  3.8  (5-15  x  3-4.7) m 

1-septate,  59  per  cent,  19  x  4.2  (12-26  x  3.5-4.7) m 
2-septate,  8  per  cent,  22.4  x  4.3  (16-35  x  4.3-5.2) /x 
3-septate,  10  per  cent,  28.1  x  5  (20-39  x  4.3-5.3) m 
4-  and  5-septate,  few,  40-45  x  5^ 

On  red  raspberry  cane  plug,  culture  seventy-three  days  old: 
Conidia:     0-septate,  39  per  cent,  12  x  4.2  (7-14  x  3-4.8) /^ 

1-septate,  50  per  cent,  14  x  4.3  (14-20  x  3.9-4.8) m 
2-septate,  11  per  cent,  22  x  4.5  (19-32  x  4. 1-5.2) /x 

On  potato  tiiber  plug,  culture  five  days  old,  kept  at  a  low  (from  3°  to 

7°  C.)  temperature: 

Conidia:     0-septate,  6  per  cent,  14  x  5.2  (10-17  x  4.8-5.5) /x 
1-septate,  53  per  cent,  16  x  5.4  (12-23  x  4.4-7)  m 
2-septate,  15  per  cent 

3-septate,  19  per  cent,  26  x  5.8  (19-42  x  5.2-7) m 
4-septate,  6  per  cent,  35  x  6.2  (33-40  x  5.4-7)  m 
5-septate,  1  per  cent,  38x6.3  (31-52  x  5.4-7)m 
6-septate,    exceptional,    41  x  6.3    (39-47  x  6-7)/i    (only    three 
measured) 

Average  of  the  above  measurements: 
Conidia:     0-septate,  23  per  cent,  11  x  4.4^ 
1-septate,  54  per  cent,  16  x  4.6^ 
2-septate,  11  per  cent,  21  x  4.8^ 
3-septate,  10  per  cent,  27  x  5.4ju 
4-septate,  2  per  cent 
5-septate,  rare,  38  x  6.3/x 
6-septate,  very  rare 

45.  Fusarium  subpallidum  n.  sp.  (Fig.  39;  PL  v,  fig.  12) 
Conidia  sickle-shaped,  typically  abruptly  constricted  at  apex,  slightly 
pedicellate  to  papillate,  somewhat  broader  in  the  middle,  mostly  5-septate, 


FusARiA  OF  Potatoes 


231 


29.1x5.53  (28-32.5  X  5.4-5.8) M,  3-  and  4-septate  common,  6-  and 
7-septate  very  rare;  chlamydospores  common,  mostly  in  long  chains; 
aerial  mycelium  well  developed;  plectenchymic  sporodochia  (up  to  3 
millimeters  in  diameter)  common;  color  of  aerial  mycelium  from  white 
to  sea-foam  yellow  and  honey  yellow;  color  of  substratum,  on  agars  rich 
in  glucose,  mostly  from  chamois  to 
raw  sienna  and  antique  brown  in 
some  old  cultures;  color  of  conidia, 
in  mass,  commonly  from  pinkish 
buff  to  pale  orange,  sometimes  from 
green  to  blue.^^ 

Hab.  On  superficial  dry  rot  of 
tubers  of  Solanum  tuberosum.  The 
organism  was  isolated  from  rotted 
potato  tubers  received  from  Edger- 
ton,  Louisiana. 

Latin  description. — Conidiis  falci- 
formibus,  typice  subito  apice  con- 
strietis,  parum  pedicellatis  demum 
papillatis,  medio  aliquatenus  lati- 
oribus,  plerumque  5-septatis,  29.1 
x5.53  (28-32.5x5.4-5.8)  At,  saepe 
etiam  conidiis  3-4-septatis ;  conidiis 
6-7-septatis  rarissimis;  chlamydo- 
sporis  frequentibus  plerumque 
longis  catenulatis;  aerio  mycelio 
plene  maturo;  plectenchymicis 
sporodochiis   (0-3  mm.   diam.)  fre- 


FiG.  39. —  Fusarium  subpallidum.  a,  Sporo- 
dochial  conidia  from  70-days-old  culture  on 
hard  -potato  agar;  b,  sporodochial  conidia 
from  35-days-old  culture  on  hard  oat  agar; 
c,  conidia  from  a  thin  slimy  layer  from  15- 
days-old  culture  on  slightly  acidified  hard 
potato  agar;  d,  conidia  from  aerial  myce- 
lium from  52-days-old  cidture  on  red  rasp- 
berry cane  plug;  e,  conidiophores  from  15- 
days-old  culture  on  slightly  acidified  hard 
potato  agar;  f,  chlamydospores  from  175- 
days-old  culture  on  corn  agar;  g,  conidio- 
phores from  52-days-old  culture  on  red  rasp- 
berry cane  plug 


quentibus;  aerio  mycelio  ex  albo 
'•sea-foam  yellow"  (R)  vel  "honey-yellow"  (R);  substrato,  in  agaribus 
perglucosis,  plerumque  e  "chamois"  (R)  "raw  sienna"  (R)  vel  etiam 
in  nonnulhs  culturis  maturis  "antique  brown"  (R);  conidiis  in  totum 
plerumque  e  "  pinkish  buff "  (R)  pallide  "orange"  (R)  vel  interdum  e 
viridi  caeruleis. 


53  A  very  exceptional  color  for  an  organism  of  the  section  Discolor,  and  observed  only  in  F.  subpallidum 
When  the  conidia  are  from  green  to  blue  in  mass,  some  of  them  appear  under  the  microscope  very  densely 
blue  as  if  stamed  with  methyl  blue.  The  same  was  observed  also  in  the  case  of  F.  coeruleum,  F.  Marlii, 
and  F.  Solani  var.  cyonum. 


232  C.  D  Sherbakoff 

Hab.  In  tuberibus  aridis  et  extra  putridis  Solani  tuberosi.  Fungus  e 
tuberibus  Solani  tuberosi  putridis  ab  Edgerton  in  Louisiana,  Amer.  bor. 
receptis,  sejungebatur. 

Measurements  of  conidia  on  various  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  fifteen  days  old;  conidia 

from  pseudopionnotes : 

Conidia:  0-septate,  rare 
1-septate,  rare 
2-septate,  rare 

3-septate,  23  per  cent,  24.4  x  5.2  (16-30'x  4.7-5.7) /x 
4-septate,  31  per  cent,  25.6  x  5.5  (19-32  x  5.2-5.9) /x 
5-septate,  45  per  cent,  28  x  5.7  (24-34  x  4.7-5.9) /x 
6-  and  7-septate,  1  per  cent,  31  x  6.1  (26-35  x  5.7-6.4)/x 

On  red  raspberry  cane  plug,  culture  fifty-nine  days  old;  conidia  from 
aerial  mycehum: 

Conidia:     3-septate,  40  per  cent,  24  x  4.7  (20-28  x  4.3-5) m 
4-septate,  18  per  cent 

5-septate,   42  per  cent,   28  x  5.2   (24-31  x  5-5.3)/x   (only  four 
measured) 

On  hard  potato  agar,  culture  one  hundred  and  seventy-five  days  old: 

(1)  Conidia  from  a  sporodochium 

Conidia:     3-septate,  4  per  cent,  26  x  5.3  (23-28  x  5.2-5.4) /x 
4-septate,  1  per  cent 
5-septate,  95  per  cent,  29  x  5.8  (26-33  x  5.2-6.  l)/x 

(2)  Chlamydospores 

0-septate,  in  conidia,  8  x  7.5  (7-9  x  6-9) ju 

1-septate,   in  mycelium,    15.5  x  10.3    (10-18  x  8.7-13.2) /x,    the 
largest  observed  being  21  x  14ju 

On  medium  soft  potato  agar,  culture  fifty  days  old: 

(1)  Conidia  from  thin  pseudopionnotes 

Conidia:     3-septate,  28  per  cent,  25  x  5.4  (26-29  x  4.8— 5.9) ju 
4-septate,  23  per  cent,  about  the  size  of  5-septate 
5-septate,  49  per  cent,  28  x  5.6  (24-32  x  5.2-6.3) /x 

(2)  Chlamydospores 

0-  and  1-septate,  in  clusters  and  chains,  7-16/x  in  diameter 


FusARiA  OF  Potatoes  233 

On  hard  oat  agar,  culture  twenty-three  days  old;  conidia  from  sporo- 
dochium : 
Conidia:     5-septate,  100  per  cent,  32.5  x  5.4  (24-35  x  5.2-5.7) m 

Average  of  the  above  measurements: 
Conidia :     0-  to  2-septate,  rare 

3-septate,  19  per  cent,  24.5  x  5.2/x 
4-septate,  15  per  cent,  25.6  x  5.5/i 
5-septate,  66  per  cent,  29.1  x  5.53/^ 
6-  and  7-septate,  very  rare,  31  x  6.1^ 

46.  Fusarium  subpallidum  var.  roseum  n.  var.  (Fig.  1,  Si  and  Ti;  PI.  iv, 
fig.  3) 

Differs  from  F.  subpallidum  by  lower  septation  of  conidia,  the  majority 
being  3-septate,  25.25x4.9  (22.5-27  x  4.7-5) /x,  and  by  a  tint  or  shade 
of  from  Tyrian  rose  to  pomegranate  purple  in  substratum  on  agars  rich 
in  glucose. 

Hab.     On  rotted  tubers  of  Solarium  tuberosum,  Kentucky. 

Measurements  of  conidia  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  fifteen  days  old;  conidia 

from  pseudopionnotes : 

Conidia:     0-septate,  few 

1-septate,  1  per  cent,  17.5  x  4.7  (10-18  x  4.7)m 
2-septate,  1  per  cent 

3-septate,  44  per  cent,  24.5  x  4.8  (18-29  x  4.7-5.3) ju 
4-septate,  35  per  cent,  27  x  4.9  (24-30  x  4.7-5.3) m 
5-septate,  19  per  cent,  29  x  5.3  (24-32  x  4.7-5.7) m 

On  red  raspberry  cane  plug,  culture  seventy-three  days  old;  conidia 
from  a  sporodochium : 
Conidia:     0-septate,  exceptional 

1-septate  \  ,  J  12  x  4. 1  (10-14  x  3.8-4.4)  m 


2-septate  j  \  23  x  4.8)u  (only  a  few  measured) 

3-septate,  34  per  cent,  26  x  5  (21-28  x  4.7-5.3) /x 
4-septate,  35  per  cent,  28  x  5.3  (23-30  x  4.8-5.7)^ 
5-septate,  30  per  cent,  30  x  5.3  (24-33  x  5-5.7) m 


234  C.  D.  Sherbakofp 

On  hard  lima-bean  agar,  culture  thirty-two  days  old;  conidia  from  a 
sporodochium : 
Conidia:     1-septate,  16  per  cent 

2-septate,  7  per  cent 

3-septate,  77  per  cent,  22.5  x  4.8  (18-25  x  4.7-5.3) /x 

4-septate,  few,  26  x  5.1  (25-30  x  4.7-5.3)/^ 

On  hard  oat  agar,  culture  twenty-three  days  old;  conidia  from  a  sporo- 
dochium : 

Conidia:     3-septate,  90  per  cent,  27  x  4.7  (24-34  x  4.1-4.9)/x 
4-septate,  9  per  cent,  29  x  4.9  (24-34  x  4.1-5.2)m 
5-septate,  1  per  cent,  33  x  4.9  (30-40  x  4.8-5.2) m 

Average  of  the  above  measurements: 
Conidia:     0-septate,  rare 

1-septate,  4.5  per  cent,  17.5  x  4.7/x 
2-septate,  2  per  cent 
3-septate,  61  per  cent,  25.25  x  4.9/i 
4-septate,  20  per  cent,  27.5  x  5.1ju 
5-septate,  12.5  per  cent,  29.5  x  5.3^ 

47.  Fusarium  clavatum  n.  sp.  (Figs.  1ri  and  40;  PI.  iii,  figs.  11  and  12; 
PL  VII,  fig.  2) 

Conidia  sickle-shaped,  typically  distinctly  broader  in  upper  third  of 
their  length,  somewhat  suddenly  constricted  at  the  apex,  slightly  pedicel- 
late, mostly  3-  to  5-septate,  5-septate  measuring  36.2  x  5.05  (32-46  x 
4.8-5.2)  m;  aerial  mycelium  of  a  medium  development  (2  to  4  millimeters 
high,  more  or  less  loose)  to  nearly  absent,  and  then  substratum  covered 
with  pseudopionnotes;  chlamydospores  scant,  not  in  long  chains;  color 
of  aerial  mycelium  and  substratum  from  white  to  light  pink  and  that  shown 
on  Plate  iii,  figures  11  and  12;  color  of  pseudopionnotes  from  pale  pink 
to  deep  ohve-buff  and  chocolate  brown  (PI.  iii,  fig.  11);  color  of  sporo- 
dochia  bright  orange  (PI.  vii,  fig.  2). 

Hab.  On  rotted  tubers  of  Solanum  tuberosum,  together  with  F.  coeru- 
leum,  Castile,  New  York. 

Latin  description. — Conidiis  falciformibus,  typice  distincte  latioribus  in  su- 
periore  tertio  longitudinis,  apice  aliquatenus  subito  constrictis,  parum  pedi- 
cellatis,  plerumque  3-5-septatis,  5-septatis,  36.2x5.05  (32-46x4.8-5.  2) /i; 
aerio  mycelio  mediocriter  maturo    (2-4  mm.    alt.,    plus  minusve    laxo) 


FusARiA  OF  Potatoes 


235 


vel  ferme  nullo,  quae  cum  ita  sint  substrate  pseudopionnotibus  obsito; 
chlamydosporis  paucis,  Don  catenulatis;  aerio  mycelio  substratoque  ex  albo 
pallide  rubello  vel  eodem  colore  quod  in  Tab.  iii,  figg.  11,  12,  exhibente; 
pseudopionnotibus  e  pallide  rubello  "olive-buff"  (R)  et  "chocolate  brown" 
(R);  sporodochiis  niticle  "orange"  (R). 

Hab.  In  tuberibus  putridis  Solani  tuberosi  una  cum  F.  coeruleo,  Cas- 
tile, New  York,  Amer.  bor. 

Measurements  of  conidia  on  various  media  are  as  follows: 

On  red  raspberry  cane  plug,  culture  ninety-two  days  old;  conidia  from 
pseudopionnotes : 
Conidia:     3-septate,  5  per  cent,  27  x  4.2  (20-35  x  4-4.7) m 

5-septate,  95  per  cent,  35  x  4.8  (29-39  x  4.3-5.7) m 


Fig.  40. —  Fusarium  clavatum.  a,  Conidia  from  a  thin  layer  near  substratum  from  92- 
daijs-old  culture  on  red  raspherrij  cane  plug  (conidia  1  and  5  are  typical,  but  in  certain  areas 
conidia  like  2,  3,  and  4  were  present  almost  to  the  exclusion  of  the  other  kinds);  b,  conidia  from 
thin  layer  from  1 20-day s-old  culture  on  potato  stem  plug;  c,  pseudopionnotal  conidia  from  4.I- 
days-old  culture  on  rye  straw;  d,  pseudopionnotal  conidia  from  32-days-old  culture  on  hard 
oat  agar;  e,  pseudopionnotal  conidia  from  10-days-old  culture  on  potato  agar;  f,  pseudopionnotal 
conidia  from  9-day  s-old  culture  on  hard  lima-bean  agar;  g,  chlamydospores  from  10-days-old 
culture  on  potato  agar 


On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  twenty-two 

days  old;  conidia  from  aerial  mycelium: 

Conidia:     3-septate,  60  per  cent,  26  x  4.9  (19-38  x  4.3-5.3) m 

4-septate,  16  per  cent,  32  x  5.2/i    (only  one  measured) 
5-septate,  24  per  cent,  32  x  5.15  (29-36  x  4.7-5.3) /x 

On  medium  soft  potato  agar,  culture  ten  days  old;  conidia  from  aerial 
mycelium  (chlamydospores  intercalary,  in  chains  and  clusters) : 
Conidia:     1-septate,  1  per  cent,  16  x  4.4/z  (only  three  measured) 
3-septate,  82  per  cent,  26  x  5  (23-31  x  4.7-5.4) /x 
4-septate,  9  per  cent,  29  x  5.1  (28-32  x  4.7-5.3) m 
5-septate,  8  per  cent,  32  x  5.2  (29-34  x  4.7-5.3)^ 


236  C.  D.  Sherbakoff 

On  hard  lima-bean  agar,  culture  nine  days  old;  conidia  from  aerial  myce- 
lium close  to  substratum : 
Conidia:     1-septate,  very  rare 

2-septate,  very  rare 

3-septate,  33  per  cent,  30  x  4.6  (19-34  x  4.3-4.8)m 

4-septate,  23  per  cent 

5-septate,  44  per  cent,  36  x  5  (33-40  x  4.6-5.4) ^ 

On  same  medium  as  above,   culture   fifteen    days   old;    conidia    from 
pseudopionnotes : 
Conidia:     2-septate,  very  rare 

3-septate,  36  per  cent,  33  x  5  (22-39  x  4.6-5.3) ^ 

4-septate,  22  per  cent 

5-septate,  42  per  cent,  36.5  x  5.1  (33^1  x  4.9-5.3)^ 

Average  of  the  above  measurements: 
Conidia:     1-septate,  rare,  16  x  4.4;U 
2-septate,  very  rare 
3-septate,  43  per  cent,  28.5  x  4.75^1 
4-septate,  15  per  cent 
5-septate,  42  per  cent,  36.2  x  5.05^ 

48.  Fusarium  discolor  Ap.  et  Wr.  (Fig.  1qi  and  41;  PI.  iv,  fig.  4;  PI.  v, 
fig.  11) 

Appel,  0.  and  Wollenweber,  H.  W.,  Arb.  K.  biol.  Anst.  Land-  u. 
Forstw.  8:108-115;  PL  i,  figs.  50  to  59;  PI.  m,  fig.  7.     1910. 

Conidia  for  greater  part  of  their  length  of  nearly  even  diameter,  sickle- 
shaped,  gradually  attenuated,  often  somewhat  suddenly  constricted  at 
the  apex,  pedicellate,  mostly  3-  to  5-septate,  5-septate  measuring  38.7  x 
5.1  (35-40  x  4.6-5. 1)m,^*  on  aerial  mycehum,  in  pseudopionnotes,  and  in 
plectenchymic  sporodochia;  chlamydospores  scant,  not  in  long  chains; 
aerial  mycelium  from  poorly  to  well  developed,  from  pale  pink-buff  to 
ochraceous  orange  and  Eugenia  red;  color  of  substratum,  on  agars  rich 
in  glucose,  from  pale  salmon  at  an  early  stage  and  warm  sepia  in  old  cul- 
tures to  tyrian  and  ox  blood ;  color  of  conidia  mostly  from  light  ochraceous 
salmon  to  ochraceous  buff. 


"  Size  of  5-septate  conidia  according  to  WoUenweber's  data  (see  Appel  and  Wollenweber  1910  :  111-112) 
is  36  X  5.1  (29-39  x  4.5-5.5)m-  The  writer's  measurements  were  taken  from  cultures  of  the  same  organ- 
ism. Average  size  of  F.  discolor  strain  isolated  in  United  States  is,  for  3-septate  conidia,  30.2  x  4.4ft 
(from 25  to  98  per  cent),  and  for  5-!3eptate  conidia, oS.4  x  4.85  (33.5-44  x  4.5-5)/i  (from  0  to  53  per  cent). 


FusARiA  OF  Potatoes 


237 


Hab.  In  stems  and  rotten  tubers  of  Solanum  tuberosum,  in  Germany 
and  in  the  United  States. 

Differs  from  F.  clavatum  mainly  by  indistinctly  clavate  conidia  and  by 
presence  of  denser  hues  of  red  color  in  substratum. 

Measurements  of  conidia  on  various  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  twenty-four  days  old; 

conidia  from  pseudopionnotes : 

Conidia:     1-septate,  rare 

3-septate,  11  per  cent,  32.3x4.3  (27-37  x  4. 1-4.9) m 
4-septate,  14  per  cent,  36  x  4.5  (32-42  x  4.3-5)  m 
5-septate,  75  per  cent,  39.2  x  4.7  (31-46  x  4.3-5.7) m 
6-septate,  few,  53  x  5.8/x  (only  one  measured) 


Fig.  41. —  Fusarium  discolor,  a,  Conidia  from  a  small  plectenchymic  sporodochium;  b, 
conidia  from  pseudopionnotes  from  15-days-old  culture  on  slightly  acidified  hard  potato  agar; 
c,  conidia  from  81 -days-old  cidture  on  red  raspberry  cane  plug;  d,  conidia  from  36-days-old 
cidture  on  potato  stem  plug;  e,  conidiophores  from  aerial  myceliujn  from  81-days-old  culture 
on  red  raspberry  cane  plug;  F,  conidiophores  from  minute  sporodochia  from  36-days-old  culture 
on  potato  stem  plug;  g,  conidia  from,  mycelial  growth  from.  41 -days-old  culture  on  rye  straw; 
H,  conidiophore  from  pseudopionnotes  from  15-days-old  culture  on  slightly  acidified  hard  potato 
agar;  i,  pseudopionnotal  conidia  from  9-days-old  culture  on  hard  lima-bean  agar;  J,  intercalary 
chlamydospore  from  culture  on  corn  agar 


On  red  raspberry  cane  plug,  culture  seventy-two  days  old;  conidia  from 

minute  sporodochia  on  aerial  mycelium: 

Conidia:     1-  and  2-septate,  rare 

3-septate,  27  per  cent,  30  x  4.4  (19-49  x  3.7-4.8)/x 
4-septate,  24  per  cent,  36  x  4.6  (26-49  x  3.9-5.9) m 
5-septate,  49  per  cent,  40  x  5.2  (32-50  x  4.9-5.9)  m 


238  C.  D.  Sherbakoff 

On  potato  tuber  plug,  culture  ninety-nine  days  old;  conidia  from  a 

sporodochium : 

Conidia:     3-septate,  6  per  cent,  26  x  4.7  (22-30  x  4.3-4.8) jn 
4-septate,  25  per  cent,  33  x  5  (28-40  x  4.6-5)  m 
5-septate,  69  per  cent,  35  x  5.2  (28-42  x  4.7-5.7) /x 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  fifty-four  days 

old;  conidia  from  a  small  sporodochium: 

Conidia:     1-  to  3-septate,  rare 

4-septate,  2  per  cent,  36  x  4.9/x  (only  two  measured) 
5-septate,  98  per  cent,  40  x  5.2  (33-44  x  4.6-5.5) /x 

On  hard   lima-bean  agar,  culture  thirty-four  days  old;   conidia  from 
pseudopionnotes : 
Conidia:     1-septate,  very  rare 

3-septate,  49  per  cent,  33.5x4.8  (24-44  x  4.1-6) ^ 

4-septate,  31  per  cent 

5-septate,  20  per  cent,  39.3  x  5.1  (31-47  x  4.6-6.2)m 

Average  of  the  a  bove  measurements : 
Conidia:     1-septate,  very  rare 
2-septate,  very  rare 
3-septate,  19  per  cent,  30.5  x  4.55^ 
4-septate,  19  per  cent 
5-septate,  62  per  cent,  38.7  x  5.1^ 
6-septate,  very  rare,  53  x  5.8^ 

49.  Fusarmm  discolor  Ap.  et  Wr.  var.  sidphureum  (Schlecht.)  Ap.  et 
Wr.  (PI.  IV,  fig.  11) 

Cf.  Schlechtendal,  Fl.  Berol.  2 :  134.  1824.  Appel,  0.,  and  Wollenweber, 
H.  W.,  Arb.  K.  biol.  Anst.  Land-  u.  Forstw.  8:115-118.     1910. 

Differs  from  F.  discolor  by  absence  of  red  color  in  mycelium  and  sub- 
stratum, and  by  entirely  exposed  pseudopionnotes  on  various  agars,  a 
characteristic  culture  of  which  is  shown  in  Plate  iv,  figure  11. 

Average  percentage  of  different  septation  types  and  sizes  of  conidia  on 
three  different  media  are  as  follows: 

Conidia:     1-septate,  about  0.5  per  cent 
2-septate,  very  rare 
3-septate,  about  25  per  cent,  28.5  x  4.2/i 


FusARiA  OF  Potatoes 


239 


4-septate,  about  28  per  cent 

5-septate,  about  46.5  per  cent,  40  x  4.9  (38-il  x  4.8-4.9) /x 
6-septate,  rare,  48  x  5.2/x 
50.  Fusarium  discolor  Ap.  et  Wr.  var.  triseptatum  n.  var.   (Figs.   Iwi 
and  42;  PI.  iv,  figs.  5  and  6;  PI.  v,  fig.  10) 

Differs  from  F.  discolor  by  dominance  of  3-septate  conidia  24.2  x  4.7 
(22-26  X  4.5-4.9) M,  by  presence  of  very  large  (up  to  1.2  centimeters  in 
diameter),  warty,  plectenchymic  bodies  (producing  conidia  or  remaining 
sterile)  of  a  pale  pinkish  buff  with  spots  of  a  darker  color,  by  more  intense 
color  of  mycelium  and  substratum  (see  Plate  iv,  figures  5  and  6),  and  by 
production  of  larger  sporodochia  with  darker  spore  masses,  much  the 
same  as  shown  for  F.  culmorum  var.  leteius  in  Plate  iv,  figure  10. 

Hab.  On  rotted  tubers  of  Solanum  tuberosum  together  with  F.  coeruleum, 
Long  Island,  New  York. 


Fig.  42. —  Fusarium  discolor  var.  triseptatum.  A,  Conidia  from  minute  aerial  sporodochia 
from  22-days-old  culture  on  slightly  acidified  hard  potato  agar;  b,  conidia  from  66-days-old 
culture  on  potato  stem  plug;  c,  conidia  from  aerial  mycelium  from  culture  on  rye  straw;  d,  conidio- 
phore  from  aerial  mycelium  from  66-days-old  culture  on  potato  stem  plug;  e,  conidia  from 
plectenchymic  sporodochia,  f,  conidiophores,  from  22-days-old  slightly  acidified  hard  potato 
agar;  g,  conidia  from  plectenchymic  sporodochia  from  9-days-old  culture  on  hard  lima-bean 
agar;  h,  basal  part  of  aerial  compound  conidiophore  from  73-days-old  culture  on  red  raspberry 
cane  plug 


Measurements  of  conidia  on  a  few  different  media  are  as  follows : 
On  slightly  acidified  hard  potato  agar,  culture  twenty-two  days  old; 
conidia  from  minute  sporodochia  on  aerial  mycelium: 
Conidia:     0-septate,  rare 

1-septate,  1.6  per  cent,  16  x  3.9 n 

2-septate,  6.4  per  cent,  18.5  x  4.3  (17-21  x  3.9-4.7)m 

3-septate,  91.2  per  cent,  22.5  x  4.5  (17-39  x  3.9-5.7)m 

4-septate,  0.8  per  cent 

5-septate,  very  rare,  31  x  5.3  (28-35  x  5.2-5.8) /x 


240  C.  D.  Sherbakoff 

On  red  raspberry  cane  plug,  culture  seventy-three  days  old;  conidia  from 

a  sporodochium : 

Conidia:     0-septate,  very  rare 

1-septate,  2  per  cent,  15  x  3.7  (10-20  x  3-4.2) m 
2-septate,  8  per  cent,  20  x  4.1  (17-23  x  3.6-4.7)/x 
3-septate,  88  per  cent,  24  x  4.6  (17-29  x  3.9-5.3)/i 
4-septate,  2  per  cent,  28  x  5.2  (25-30  x  4.8-5.7)/* 

On  hard  lima-bean  agar,  culture  nine  days  old;  conidia  from  a  young 
plectenchymic  sporodochium : 
Conidia:     1-septate,  2  per  cent 

2-septate,  3  per  cent,  20  x  4.5  (13-25  x  4.1-4.7) m 

3-septate,  88  per  cent,  26  x  4.9  (18-33  x  4.2-6) m 

4-septate,  6  per  cent 

5-septate,  1  per  cent,  30  x  5.8//  (only  a  few  measured) 

Average  of  the  above  measurements: 
Conidia:     0-septate,  very  rare 

1-septate,  2  per  cent,  15.5  x  3.8/t 
2-septate,  6  per  cent,  19.5  x  4.3 /t 
3-septate,  89  per  cent,  24.2  x  4.7/t 
4-septate,  3  per  cent,  29.5  x  5.25/i 
5-septate,  few,  30.5  x  5.55/t 

The  organism  seems  to  be  so  different  from  F.  discolor  that  one  may 
wonder  why  it  is  considered  as  a  variety  rather  than  an  independent 
species,  especially  in  view  of  the  fact  that  there  are  some  organisms 
designated  as  species  which  apparently  differ  very  slightly  from  the 
other  related  species.  The  explanation  lies  mainly  in  the  fact  that, 
notwithstanding  a  seemingly  great  difference,  this  difference  is  in  unstable 
characters  —  greater  proportion  of  one  type  of  septation  instead  of 
another,  denser  color,  larger  sporodochia,  and  so  forth  —  and,  moreover, 
in  certain  instances  the  two  organisms  approach  each  other  so  closely 
as  to  be  distinguished  only  with  considerable  difficulty  if  at  all. 

51.  Fusarium  cuhnorum  (W.  Smith)  Sacc.   (PI.  iv,  fig.  9;  PI.  v,  fig.  8) 
Cf.  Wollenweber,  H.  W.,  Journ.  Agr.  Research    2:260-261,  PI.  xvi, 
fig.  J.     1914. 


FusARiA  OF  Potatoes  241 

Syn.  Fusarium  culmorum  W.  G.  Smith,  Dis.  Field  and  Gard.  Crops,  pp.  208-210,  fig.  92. 

1884. 
Fusarium  Schribauxi  Delacr.,  Bui.  Soc.  Mycol.  France  6:99,  pi.  15,  fig.  1.     1890.     Sac- 

cardo,  Syll.  Fung.  10:726.     1890. 
Fusarium  culmorum  (W.  Sm.)  Sacc,  Syll.  Fung.  11:651.     1895. 
Fusarium  corallinum  Mattirolo  (non  Sacc),  Mem.  R.  Accad.  Sci.  1st.  Bologna,  ser. 

5:6:677,  figs.  16  and  17.     1897. 
Fusarium  rubiginosum  Ap.  et  Wr.,  Arb.  K.  biol.  Anst    Land-  u.   Forstw.  8:95-108; 

text  fig.  8;  PI.  I,  figs.  31  to  48.     1910. 

Coniclia  for  a  greater  part  of  their  length  of  an  even  diameter,  mostly 
5-septate,  38.5x5.85  (37-40x5.3-6.2)//,  somewhat  suddenly  constricted 
at  apex;  pedicellate,  of  distinctly  ochraceous  orange  color  under  micro- 
scope; chlamydospores  of  more  or  less  common  occurrence  in  mycelium 
and  in  conidia,  not  in  long  chains;  aerial  mycelium  well  developed,  high 
(up  to  1  centimeter  and  more),  very  loose,  at  first  from  white  to  pinkish 
cinnamon,  and  then  to  jasper  and  Eugenia  red;  substratum,  on  potato 
agar  rich  in  glucose,  of  from  spectrum  red  to  carmine-pomegranate  purple, 
with  more  or  less  brick  red  color;  color  of  conidia  in  mass  from  cinnamon 
and  light  ochraceous  to  mikado  brown  and  warm  sepia;  sporodochia 
minute,  separate  or  converging  into  pseudopionnotes. 

Hab.  On  cereals  and  on  potato  tubers  and  some  other  hosts,  in  Europe 
and  the  United  States. 

The  organism  was  isolated  by  the  writer  from  rotted  potato  tubers, 
alone  and  in  association  with  other  Fusaria. 

Measurements  of  conidia  on  different  media  are  as  follows :  ^^ 

On  slightly  acidified  hard  potato  agar,  culture  twenty-three  days  old; 

conidia  from  pseudopionnotes: 

Conidia:     3-septate,  5  per  cent,  33  x  5.9  (21-36  x  4.7-6.1)m 
4-septate,  10  per  cent,  35  x  6.1  (30-37  x  5.7-6.4)/x 
5-septate,  85  per  cent,  37  x  6.2  (32-46  x  5.2-6.5)^ 

On  red  raspberry  cane  plug,  culture  seventy-two  days  old: 
(1)  Conidia  from  a  sporodochium 
Conidia:     3-septate,  3  per  cent 

4-septate,  10  per  cent 

5-septate,  87  per  cent,  40  x  6.2  (33-53  x  5.8-7) m 

65  Average  of  the  measurements  given  by  Appel  and  Wollenweber  (1910  :10G)  is  as  follows: 
CoDidia:     0-  to  2-septate,  about  1  per  cent 

3-septate,  about  11  per  cent,  26  x  5.5/1 

4-septate,  about  13  per  cent,  27  x  5.7ju 

5-septate,  about  74  per  cent,  39  x  6.1/i 

6-septate,  about  1  per  cent,  45  x  6/i 


242  CD.  Sherbakoff 

(2)  Conidia  from  aerial  mycelium 
Conidia:     3-septate,  60  per  cent,  30  x  4.7  (19-39  x  4. 1-5.9)  m 
4-septate,  25  per  cent,  37  x  5  (31-42  x  4.4-5.9)  m 
5-septate,  15  per  cent,  39  x  5.3  (35-43  x  5.2-5.9) /x 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  one  hundred 
and  fifty-four  days  old;  conidia  from  pseudopionnotes : 
Conidia:     0-septate,  rare,  8  x  4;u  (only  a  few  measured) 

1-septate,  rare,  12  x  3.7)u  (only  a  few  measured) 

2-septate,  rare 

3-septate,  3  per  cent,  26  x  4.7  (17-34  x  4.1-5.5)/x 

4-septate,  7  per  cent 

5-septate,  89  per  cent,  38  x  5.7  (33-47  x  5.2-6.1) ]« 

6-septate,  1  per  cent,  49  x  5.7/i  (only  a  few  measured) 

7-septate,  very  rare,  56  x  6.1/i  (only  a  few  measured) 

Average  of  the  above  measurements: 
Conidia:     0-septate,  very  rare,  8  x  4/i 

1-septate,  very  rare,  12  x  37/* 

2-septate,  very  rare 

3-septate,  18  per  cent,  29.67  x  S.ljtt 

4-septate,  13  per  cent 

5-septate,  69  per  cent,  38.5  x  5.85/i 

6-septate,  few,  49  x  5.7/x 

7-septate,  exceptional,  56  x  6.1/x 

52.  Fusarium  culmorum  (W.  Smith)  Sacc.  var.  leteius  n.  var.  (Figs.  ID2 
and  43;  PL  iv,  figs.  1,  2,  10;  PI.  v,  fig.  9) 

Differs  from  F.  culmorum  mainly  by  somewhat  comma-like  conidia 
from  aerial  mycelium,  by  typical  presence  of  medium  large  (up  to  from 
3  to  5  millimeters  in  diameter)  sporodochia,  and  by  somewhat  broader 
average  size  of  conidia. 

Hab.  On  rotted  tubers  of  Solanum  tuberosum,  Atlanta  and  Forks, 
New  York. 

Measurements  of  conidia  on  different  media  are  as  follows: 


FusARiA  OF  Potatoes 


243 


On  slightly  acidified  hard  potato  agar,  culture  fifteen  days  old;  conidia 

from  a  sporodochium: 

Conidia:  1-septate,  0.5  per  cent,  18  x  5.2  (14-22  x  4.7-5.9)At 
2-septate,  5.5  per  cent,  23  x  6.9  (20-26  x  6.4-7.9 V 
3-septate,  34  per  cent,  26.5  x  7  (21-33  x  5.6-7.6) m 
4-septate,  38  per  cent,  33.2x7.3  (26-38  x  6.4-7.9) ^ 
5-septate,  22  per  cent,  36.4  x  7.5  (31^4  x  7-8.8) m 
6-septate,  very  few,  44.5  x  8.9;u    (only  one  measured) 


Fig.  43. —  Fusarium  culmorum  var.  leteius.  a,  Conidia,  b,  conidiophores,  from  aerial  sporo- 
dochium from  15-daxjs-old  culture  on  slightly  acidified  hard  potato  agar;  c,  conidiophore  from 
11 -days-old  culture  on  hard  lima-bean  agar;  d,  conidia  from  plectenchymic  sporodochium,  e,  f,  g, 
conidiophores,  from  72-days-old  culture  on  red  raspberry  cane  plug;  h,  intercalary  chlamydospores 
from  175-days-old  culture  on  corn  agar;  i,  conidia  from  plectenchymic  sporodochium  from  11- 
days-old  culture  on  hard  lima-bean  agar;  j,  intercalary  chlamydospores  from  175-days-old  culture 
on  corn  agar  (some  chlamydospores  producing  conidiophores);  k,  conidia  from  aerial  sporodochia 
from  72-days-old  culture  on  red  raspberry  cane  plug;  i.,  tip  of  aerial  hypha  showing  prominent 
swellings  {magnification  250  times) 

On  red  raspberry  cane  plug,  culture  seventy-two  days  old: 
(1)  Conidia  from  a  plectenchymic  sporodochium  borne  directly  on  the 
plug 
Conidia:     3-septate,  14  per  cent 
4-septate,  20  per  cent 
5-septate,  66  per  cent,  43  x  6.2  (31-53  x  5.8-7) /z 


244  C.  D.  Sherbakoff 

(2)   Conidia  from  a  bushlike  sporodochium  borne  on  aerial  mycelium 
Conidia:     1-  and  2-septate,  very  few 

3-septate,  40  per  cent,  29  x  6.9  (26-35  x  6-7.8) /x 
4-septate,  30  per  cent,  32x6.8  (29-36  x  6-7.5) /x 
5-septate,  30  per  cent,  37  x  6.8  (31-42  x  6.3-7.5)^ 

On  hard  lima-bean  agar,  culture  eleven  days  old ;  conidia  from  a  sporo- 
dochium (only  mature  spores  measured) : 
Conidia:     1-septate,  2  per  cent 

3-septate,  26  per  cent,  32  x  6.1  (24-37  x  5.2-6.7) /x 

4-septate,  37  per  cent 

5-septate,  35  per  cent,  39  x  5.9  (30-44  x  5.3-6.7) /x 

Average  of  the  above  measurements: 
Conidia:     1-septate,  0.5  per  cent,  18x5.2^ 
2-septate,  1.5  per  cent,  23.5  x  6.9/x 
3-septate,  28  per  cent,  27.2  x  6.7/x 
4-septate,  31  per  cent 
5-septate,  39  per  cent,  38.85  x  6.6m 
6-septate,  exceptional,  44.5  x  8.9ju  (only  one  measured) 

XL  Section  Martiella  Wr.  (Fig.  1,  Xi  to  C2).  Wollenweber,  H.  W., 
Phytopath.  3:30,  Fig.  1,  a  to  c.  1913 
Microconidia  on  aerial  mycelium  typically  present,  from  oval  to  oblong, 
mostly  0-septate;  macroconidia  mostly  3-septate,  of  nearly  even  diameter 
throughout  or  but  slightly  broader  either  toward  apex  or  toward  base, 
nearly  straight  in  lower  half  and  more  or  less  curved  near  apex,  with 
somewhat  rounded  apex  or  only  slightly  pointed  or  constricted,  typically 
from  slightly  pedicellate  to  apedicellate;  aerial  mycelium  mostly  from 
white  to  a  light  tint  of  chamois  and  drab  hues;  substratum,  on  neutral 
agars,  never  rose-pink  nor  pomegranate  purple  in  color,  sometimes 
from  vinaceous  to  blue;  color  of  conidia,  except  in  acid  media,  mostly  from 
pale  buff  to  drab,  often  distinctly  from  green  to  blue. 

53.  Fusarium  Martii  Ap.  et  Wr.  (Figs.  1,  Zi  and  A2,  and  44m) 
Appel,  O.,  and  Wollenweber,    H.  W.,  Arb.  K.  biol.  Anst.  Land-  u. 
Forstw.  8:78-84,  text  fig.  5.     1910. 

Macroconidia    mostly    3-septate,    43.9x5.15    (42-46  x  4.9-5.3) /x,    and 


FusARiA  OF  Potatoes 


245 


4-septate,  49.3  x  5.3  (48-50  x  4.9-5.4) /x,  often  also  5-septate,  typically, 
when  mature,  of  from  deep  lichen  and  montpellier  green  (on  corn  meal 
agar)  to  light  olive-drab  (on  potato  agar  rich  in  glucose)  and  often  to 
dark  blue  (on  potato  tuber  plug)f^  macroconidia  usually  produced  in 
abundance  in  small  sporodochia  and  in  pseudopionnotes ;  chlamydospores 
terminal  and  intercalary,  single,  in  clusters,  and  in  short  chains,  mostly 
0-septate,  9.25x8.16  (8-11.3  x  7.5-9.3) m;  aerial  mycelium  typically  me- 
dium short  (from  1  to 4 millimeters),  loose,  more  or  less  coarsely  powdered 
with  conidia,  and  typically,  on  potato  agar  rich  in  glucose,  of  from  smoke 
gray  to  sometimes  Charturadrab  color;  the  substratum  on  the  same  kind 
of  medium  being  mostly  of  from  tawny  olive  to  sepia  in  color. 


Fig.  44. —  a-i,  Fusarium  Martii  var.  viride.  a,  Pseudopionnotal  conidia  {the  stippled  one 
showing  dense  grantdation  of  the  protoplasm  masking  septation),  b,  conidiophores  (magnification 
250  tiynes),  from  11 -days-old  culture  on  slightly  acidified  hard  potato  agar;  c,  conidia  showing 
dense  granulation  of  the  protoplasm  containing  from  small  to  large  oil  globules  from  29-days-old 
culture  on  rye  straw;  d,  chlamydospores,  terminal  and  intercalary,  e,  pseudopionnotal  conidia, 
from  71 -days-old  culture  on  potato  tuber  plug;  F,  conidiophore  from  70-day s-old  culture  on 
potato  stem  plug;  g,  conidia,  h,  conidiophore,  from  ^7 -days-old  culture  on  stem  plug;  i,  pseudo- 
pionnotal conidia  from  64-days-old  culture  on  potato  tuber  plug  ' 

J-L,  Fusarium  Martii  var.  minus,  j,  conidia  from  plectenchymic  sporodochium  from  71- 
days-old  culture  on  potato  tuber  plug;  k,  sporodochial  conidia  from  85-days-old  culture  on  red 
raspberry  cane  plug;  Ka,  microconidia  from  aerial  mycelium;  l,  basal  part  and  one  branch 
of  compound  conidiophore  from  71 -days-old  culture  on  potato  stem  plug 

M,  Fusarium  Martii,  pseudopionnotal  conidia  from  11-days-old  culture  on  slightly  acidified 
hard  potato  agar 

"  The  culture  media  are  mentioned  here  merely  because  the  colors  were  oftener  observed  on  these  media 
than  on  others;  in  fact,  a  green  color  in  conidia  is  often  produced  also  on  potato  tuber  plugs  and  on  some 
other  media,  and  the  same  is  true  of  a  blue  color.  The  color  is  due  to  color  of  conidia,  not  to  color  of 
substratum  alone,  as  can  be  observed  under  the  microscope. 


246  C.  D.  Sherbakoff 

Hab.  On  rotted  tubers  of  Solanuin  tuberosum  and  on  other  plants,  in 
the  United  States  and  in  Europe.  The  organism  was  isolated  by  the 
writer  from  specimens  received  from  various  States. 

Measurements  of  conidia  on  different  media  are  as  follows: 

On  potato  tuber  plug,  culture  seventy  days  old;  conidia  from  pseudo- 

pionnotes : 

Conidia:     0-septate,  rare 

1 -septate,  3  per  cent 

2-septate,  rare 

3-septate,  60  per  cent,  46  x  5.3  (38-51  x  5.2-5.7) fx 

4-septate,  30  per  cent,  50  x  5.4  (43-54  x  5.2-5.9)At 

5-septate,  7  per  cent,  52  x  5.6  (45-54  x  5.2-5.9) m 

On  slightly  acidified  hard  potato  agar,  culture  eleven  days  old;  conidia 

from  thin  pseudopionnotes : 

Conidia:  0-septate,  2  per  cent,  11  x4m 
1-septate,  2  per  cent,  20  x  4.5fx 
2-septate,  rare 

3-septate,  23  per  cent,  43.5  x  5.2  (33-51  x  4.6-5.3) ^i 
4-septate,  68  per  cent,  49  x  5.6  (42-65  x  4.6-6.7)/^ 
5-septate,  5  per  cent,  60x5.85  (56-63  x  5.6-6.45) /x 

On  red  raspberry  cane  plug,  culture  eighty-two  days  old ;  conidia  from  a 

sporodochium: 

Conidia:     1-  and  2-septate,  rare 

3-septate,  57  per  cent,  44  x  5.1  (29-50  x  4.3-5.9) /x 
4-septate,  43  per  cent,  51  x  5.3  (40-54  x  4.7-5.9) m 
5-septate,  rare,  54  x  5.4/i  (only  one  measured) 

On  potato  tuber  plug,  culture  sixty-four  days  old;  conidia  from  thick 

pseudopionnotes : 

Conidia:     0-septate,  rare,  about  9  x  3.5/1 

3-septate,  55  per  cent,  43  x  4.9  (28-50  x  4.7-5.1)/x 
4-septate,  45  per  cent,  48  x  4.9  (43-55  x  4.7-5.7)/x 
5-septate,  very  rare 


FusARiA  OF  Potatoes  247 

On  hard  lima-bean  agar,  culture  sixty-eight  days  old;  conidia  from  a 

small  sporodochium: 

Conidia:     0-  to  2-septate,  very  rare 

3-septate,  48  per  cent,  42  x  5.2  (30-51  x  4.8-5.9)/x 
4-septate,  50  per  cent,  48  x  5.3  (41-53  x  4.8-5.9) /x 
5-septate,  2  per  cent,  51  x  5.5  (43-56  x  5-5.9) ju 

On  same  medium  and  of  same  age  as  above,  conidia  from  a  medium 
large  (about  2  millimeters  in  diameter),  short,  column-like  sporodochium: 
Conidia:     0-  to  2-septate,  very  rare 

3-septate,  49  per  cent,  45  x  5.2  (36-49  x  4.5-5.6)/i 
4-septate,  51  per  cent,  50  x  5.2  (38-56  x  4.8-5.6V 
5-septate,  very  rare 

Average  of  the  above  measurements: 
Conidia:     0-septate,  rare,  11  x4m 

1-septate,  1  per  cent,  20  x  4.5/x 
2-septate,  very  rare 
3-septate,  53  per  cent,  43.9  x  5.15/i 
4-septate,  43  per  cent,  49.3  x  5.3/i 
5-septate,  3  per  cent,  54.3  x  5.57 ij, 

The  average  sizes  given  by  Appel  and  Wollenweber  for  the  same  fungus 
are: 
Conidia:     3-septate,  about  44  per  cent,  49  x  5.25)U 

4-septate,  about  51.5  per  cent,  55  x  5.5/i 

5-septate,  about  4.5  per  cent,  56.5  x  5.5/x 

54.  Fusarium  Martii  Ap.  et  Wr.  var.  viride  n.  var.  (Fig.  44,  a  to  i;  PI. 
VI,  fig.  5) 

Differs  from  F.  Martii  by  having  macroconidia  somewhat  narrower, 
and  usually  by  a  paler  color  of  conidia  and  substratum;  dark  blue  color 
of  conidial  masses  not  observed.  Typical  color  of  conidia  in  mass,  on 
potato  agar  rich  in  glucose,  pale  smoke-gray,  and  of  substratum  pale  drab- 
gray. 

Hab.  In  discolored  fibrovascular  bundles  of  Solanum  tuberosum,  in 
stems  and  tubers,  at  Atlanta  and  Castile,  New  York. 

Measurements  of  conidia  on  various  media  are  as  follows: 


248  C.  D.  Sherbakoff 

On   potato   tuber   plug,   culture   seventy-one   days  old;  conidia  from 
pseudopionnotes : 
Conidia:     0-septate,  4  per  cent 

1-septate,  22  per  cent 

2-septate,  10  per  cent 

3-septate,  60  per  cent,  39  x  5  (33-43  x  4.6-5.2) m 

4-septate,  4  per  cent 

On  slightly  acidified  hard  potato  agar,  culture  eight  days  old;  conidia 

from  pseudopionnotes : 

Conidia:     0-septate,  rare,  9  x  4/i 
1-septate,  rare,  17  x  5/x 
2-septate,  rare 

3-septate,  41  per  cent,  about  46  x  5  (42-51  x  4.4-5.25) /z 
4-septate,  58  per  cent,  54.4  x  5.25  (45-68  x  4.8-5.6)// 
5-septate,  1  per  cent,  58.5  x  5.7  (50-62  x  5-6) /x 

On  red  raspberry  cane  plug,  culture  eighty-six  days  old;  conidia  from 
a  sporodochium : 

Conidia:     3-septate,  50  per  cent,  45  x  5.2  (36-53  x  5-5.4) /x 
4-septate,  50  per  cent,  54  x  5.4  (42-61  x  5.2-5.9) ^ 

On  hard  lima-bean  agar,  culture  twenty-two  days  old;  conidia  from 
pseudopionnotes: 
Conidia:     3-septate,  90  per  cent,  46.1  x  5  (40-49  x  4.7-5.3) m 

4-septate,  9  per  cent 

5-septate,  1  per  cent 

On  potato  tuber  plug,  culture  sixty-four  days  old;  conidia  from  thick 
pseudopionnotes : 

Conidia:     3-septate,  55  per  cent,  45  x  4.9  (40-49  x  4.8-5.3)^ 
4-septate,  45  per  cent,  49  x  5.3  (45-53  x  5-5.6) /x 

On  hard  lima-bean  agar,  culture  seventy-two  days  old;  conidia  from  a 
columnar  sporodochial  mass: 

Conidia:     3-septate,  73  per  cent,  45  x  5.1  (40-49  x  4.7-5.3) /x 
4-septate,  27  per  cent,  50  x  5.2  (47-51  x  5-5.6) /x 


FusARiA  OF  Potatoes  249 

Average  of  the  above  measurements: 
Conidia:     0-septate,  0.5  per  cent,  9  x  4/x 
1-septate,  3  per  cent,  17  x  5/x 
2-septate,  1  per  cent 
3-septate,  63  per  cent,  44.4  x  5.03/* 
4-septate,  32  per  cent,  51.9  x  5.27;u 
5-septate,  0.5  per  cent,  58.5  x  5.7 fx 

55.  Fusarium  Martii  Ap.  et  Wr.  var.  minus  n.  var.  (Fig,  44,  j  to  l; 
PL  1,  figs.  3  and  4;  PI.  vi,  fig.  6) 

Differs  from  F.  Martii  and  F.  Martii  var,  viride  by  having  smaller,  3- 
septate,  conidia,  36.7x4.8  (30-44  x  4.55-5, l)/i,  usually  prominent  de- 
velopment of  pleotenchymic,  wartlike  stromata,  and  fewer  and  larger 
sporodochia  (PI,  vi,  fig.  6). 

Color  of  substratum,  on  potato  agar  rich  in  glucose,  from  light  gray  to 
drab  and  dark  olive-buff,  with  a  fuscous-colored  spot  at  the  point  of 
inoculation  (PI.  i,  figs.  3  and  4). 

Hab.  On  rotted  tubers  of  Solarium  tuberosinn,  evidently  following 
Phytophthora  infestans,  Dutchess  County,  New  York. 

Measurements  of  conidia  on  different  media  are  as  follows : 

On  potato  tuber  plug,  culture  seventy-one  days  old: 

(1)  Conidia  from  a  sporodochium 
Conidia:     0-septate,  8  per  cent 

1-septate,  13  per  cent 
2-septate,  29  per  cent 
3-septate,  50  per  cent,  30  x  4.6  (26-33  x  3.6-4.8)m 

(2)  Conidia  from  pseudopionnotes 
Conidia:     1-septate,  9  per  cent 

2-septate,  37  per  cent 

3-septate,  54  per  cent,  30  x  4.55  (27-34  x  3.9-4.8)/z 

(3)  Conidia  from  oldest  part  of  pseudopionnotes 
Conidia:     3-septate,  100  per  cent,  37  x  4.7  (27^3  x  4.2-5) /x 

On  slightly  acidified  hard  potato  agar,  culture  eleven  days  old;  conidia 

from  pseudopionnotes: 

Conidia:     3-septate,  67  per  cent,  43.75  x  4.6  (24-52  x  3.5-5.3)m 
4-septate,  28  per  cent,  48.65  x  5  (43-53  x  4.3-5.3)/x 
5-septate,  5  per  cent,  52.85  x  5  (50-57  x  4.3-5.3) m 


.250  CD.  Sherbakoff 

On  red  raspberry  cane  plug,  culture  eighty-five  days  old;  conidia  from 

a  sporodochium: 

Conidia:  0-septate,  rare 
1-septate,  rare 
2-septate,  rare 

3-septate,  80  per  cent,  38  x  5.1  (28-48  x  4.1-5.3)jLt 
4-septate,  20  per  cent,  47  x  5.2  (^2-52  x  4.9-5.5) m 
5-septate,  rare,  47  x  5.2^t  (only  Ox^e  measured) 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  twenty-two 
days  old: 

Conidia:     3-septate,  88  per  cent,  41.4  x  4.7  (36-47  x  4.1-5.3)^ 
4-septate,  10  per  cent 
5-septate,  2  per  cent 

On  potato  tuber  plug,  culture  sixty-four  days  old;  conidia  from  pseudo- 
pionnotes : 
Conidia:     0-septate,  very  rare 

3-septate,  86  per  cent,  40  x  4.8  (33-49  x  4. 1-5.2) m 
4-septate,  14  per  cent,  48  x  4.9  (38-56  x  4.7-5.7) yu 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  sixty-eight 

days  old;  conidia  from  a  columnar  mass: 

Conidia:     0-  to  2-septate,  very  rare 

3-septate,  93  per  cent,  40  x  5.1  (30-45  x  4.7-5.4) ^ 
4-septate,  7  per  cent,  44  x  5.1  (36-48  x  4.7-5.4) /i 
5-septate,  very  rare,  47  x  5.3^i  (only  one  measured) 

On  same  medium,  culture  also  same  age;  conidia  from  pseudopionnotes : 
Conidia:     0-  to  2-septate,  very  rare 

3-septate,  98  per  cent,  41  x  5  (33-42  x  4.7-5.3)m 
4-septate,  2  per  cent,  44  x  5.1  (40-50  x  4.8-5.3) /x 

Average  of  the  above  measurements: 
Conidia:     0-septate,  11  per  cent 
1-septate,  2  per  cent 
2-septate,  6.6  per  cent 
3-septate,  71.6  per  cent,  36.7  x  4.8/x 
4-septate,  8.1  per  cent,  46.2  x  5.06/x 
5-septate,  0.7  per  cent,  50  x  5.17/i 


FusARiA  OF  Potatoes 


251 


56.  Fusarium  Solani  (Mart.  p.  par.)  Ap.  et  Wr.  (Fig.  1,  Xi  and  Yi; 
Fig.  45,  a  to  g;  PI.  i,  fig.  1;  PI.  vi,  fig.  7) 

Appel,  O.,  and  Wollenweber,  H.  W.,  Arb.  K.  bid.  Anst.  Land-  u. 
Forstw.  8: 64-78;  PL  i,  figs.  1  to  30;  PL  m,  fig.  1 ;  text  fig.  4.     1910. 

Microconidia  always  present,  at  least  on  aerial  mycelium,  same  size  and 
shape  as  those  of  F.  Martii.     Macroconidia  typically  somewhat  broader 


Fig.  45. —  a-g,  Fusarium  Solani.  a,  Conidia  from  pledenchymic  sporodochia  from  66-days- 
old  culture  on  potato  tuber  plugs;  b,  conidiophores,  c,  conidia,  from  aerial  vnjcelium  from  12- 
day  s-old  culture  on  hard  lima-bean  agar;  d,  pseudopionnotal  conidia  from  11 -days-old  culture 
on  slightly  acidified  hard  potato  agar;  e,  conidia  from  sporodochium  from  87-days-old  culture 
on  red  raspberry  cane  plug;  f.  terminal,  1-  to  3-septate,  chlamydospores  produced  by  hyphce  and 
conidia,  the  latter  anastomosed,  from  173-days-old  culture  on  corn  agar;  g,  terminal  and  inter- 
calary, clustered,  chlamydospores  from  70-days-old  cidture  on  potato  tuber  plug 

H-j,  Fusarium  Solani  var.  cyanum.  h,  Sporodochial  conidia  from  87-days-old  cidture  on 
red  raspberry  cane  plug;  i,  pseudopionnotal  conidia  from  15-day  s-old  culture  on  slightly  acidified 
hard  potato  agar;  j,  aerial  conidia  from  87-days-old  cidture  on  red  raspberry  cane  plug 

K-T,  Fusarium  Solani  var.  suffuscum.  k,  Pseudopionnotal  conidia  from  7-days-old  colony 
in  petri  dish  on  hard  potato  agar  (the  middle  spore  above  is  typical  for  the  culture);  l,  sporodochial 
conidia  from  Jt7 -days-old  culture  on  rye  straiv  {many  conidia  have  coarsely  granulated  protoplasm 
and  oil  globules);  m,  compound  conidiophore  inform  of  dense  tuft  {looking  from  above,  magnifi- 
cation 250  times),  from  47 -days-old  culture  on  potato  stem  plug;  n,  chlamydospores,  o,  sporo- 
dochial conidia,  from  70-days-old  cultu  e  rn  potato  tuber  plug;  v,  typical  ends  of  conidiophores 
from  47-days-old  culture  on  potato  stem  plug;  q,  sporodochial  conidia  from  87-days-old  culture 
on  red  raspberry  cane  plug;  r,  sporodochial  conidia  and  conidiophore  from  13-days-old  culture 
on  potato  tuber  plug;  s,  sporodochial  con'dia  from  16-days-old  culture  on  slightly  acidified  hard 
potato  agar;  t,  sporodochial  conidia  from  47-days-old  culture  on  potato  stem  plug 


252  C.  D.  Sherbakoff 

in  upper  half  of  their  length,  with  from  rounded  to  slightly  constricted 
apex,  not  at  all  or  slightly  pedicellate,  typically  3-septate,  29.75  x  5.5 
(27-34.7  X  5.4-5.8) /x,  sometimes  4-septate,  rarely  5-septate;  aerial  myce- 
lium from  poorly  to  well  developed,  from  white  to  olive-buff;  substratum, 
on  potato  agar  rich  in  glucose,  olive-buff  with  a  green-blue  tinge  (PI.  i, 
fig,  1,  and  PI.  VI,  fig.  7). 

Hab.  On  Solanum  tuberosum  and  other  substrata,  in  Europe  and  America; 
often  in  association  with  other  Fusaria. 

The  organism  was  often  isolated  by  the  writer  from  rotted  potato  tubers 
received  from  various  States. 

Measurements  of  conidia  on  various  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  eleven  days  old;  conidia 

from  pseudopionnotes : 

Conidia:     1-septate,  0.5  per  cent,  14x4  (13-17  x  3.5-5. 8) /x 
2-septate,  1  per  cent,  22x4.5  (17-28  x  4.2-4.8) /x 
3-septate,  93  per  cent,  34.7  x  5.4  (22-42  x  4.3-6. l)/x 
4-septate,  5  per  cent,  38  x  5.8  (30-43  x  5-6.4) m 
5-septate,  0.5  per  cent,  44.3  x  5.8  (38-47  x  5-6.4) /x   ■ 

On  potato  tuber  plug,  culture  sixty-five  days  old ;  conidia  from  a  sporo- 

dochium: 

Conidia:     0-septate,  rare,  8.7  x  4)u  (only  a  few  measured) 
1-septate,  2  per  cent,  20  x  4.6ju 
2-septate,  4  per  cent,  23x4.7  (18-25  x  4.4-5.4) m 
3-septate,  93  per  cent,  28  x  5.8  (22-35  x  4.8-6.  l)/x 
4-septate,  1  per  cent,  33-5.9  (28-38  x  5.4-6. l)/x 

On  hard  lima-bean  agar,  culture  twelve  days  old: 

(1)  Conidia  from  aerial  mycelium 
Conidia:     0-septate,  20  per  cent 

1-septate,  40  per  cent 
2-septate,  19  per  cent 
3-septate,  21  per  cent,  27  x  5.4  (24-37  x  4.7-6)/* 

(2)  Conidia  from  a  sporodochium 
Conidia:     0-septate,  1  per  cent 

1-septate,  1  per  cent 
2-septate,  1  per  cent 
3-septate  (97  to  100  per  cent),  29.3  x  5.4  (24-35  x  4.8-5.9) m 


FusARiA  OF  Potatoes  253 

Average  of  the  above  measurements: 
Conidia:     0-septate,  5  per  cent,  8.7  x  4/i 

1-septate,  11  per  cent,    17  x  4.3/x 
2-septate,  6  per  cent,  22.5  x  4.6ai 
3-septate,  76.5  per  cent,  29.75  x  5.5/t 
4-septate,  1.5  per  cent,  35.5  x  5.85 ;u 
5-septate,  rare,  44.3  x  5.8ju 

57.  Fusarium  Solani  (Mart.  p.  par.)  Ap.  et  Wr.  var.  cyanum  n.  var. 
(Fig.  45,  H  to  j) 

Differs  from  F.  Solani  mainly  by  having  macroconidia  typically  more 
rounded  at  apex  and  base,  by  fewer  4-septate  and  absence  of  5-septate 
conidia,  and  by  frequent  occurrence  of  bluish  plectenchyma  (on  hard  bean 
agar  and  potato  tuber  plugs) ;  sometimes  dist'nct  blue  color  in  conidia  also 
observable;  size  for  the  same  septation  type  of  conidia  almost  the  same 
as  that  of  F.  Solani. 

Hab.     Same  as  for  F.  Solani,  but  much  less  common. 

On  potato  tuber  plug,  culture  sixty-eight  days  old;  conidia  from    a 
sporodochium : 
Conidia:     0-septate,  28  per  cent 

1-septate,  22  per  cent 

2-septate,  35  per  cent 

3-septate,  15  per  cent,  28  x  5.2  (24-31  x  4.8-5.7) m 

On  slightly  acidified  hard  potato  agar,  culture  fifteen  days  old;  conidia 

from  pseudopionnotes: 

Conidia:     0-septate,  14  per  cent,  12  x  3.7  (8.7-14  x  2.5-5) ^ 

1-septate,  22  per  cent,  24.5  x  4.5  (15-30  x  3.5-5.3)m 
2-septate,  19  per  cent,  29  x  5  (24-32  x  4.8-5.3) m 
3-septate,  45  per  cent,  33  x  5.7  (31-35  x  5-6)m 

On  red  raspberry  cane  plug,  culture  eighty-seven  days  old;  conidia  from 

a  sporodochium : 

Conidia:     0-septate,  few 

1-septate,  3  per  cent 

2-septate,  5  per  cent,  25  x  5.5  (19-27  x  4.7-5.8)^ 
3-septate,  90  per  cent,  30  x  5.7  (28-35  x  5.2-5.9)^ 
4-septate,  2  per  cent,  35  x  5.5  (33-37  x  5.2-5.7) /x 


254  C.  D.  Sherbakoff 

On  potato  tuber  plug,  culture  sixty-five  days  old;  conidia  from  a  sporo- 
dochium: 

Conidia:     0-septate,  few 

1-septate,  12  per  cent,  about  22  x  5/x  (only  one  measured) 
2-septate,  16  per  cent,  about  27  x  5.3/x  (only  one  measured) 
3-septate,  72  per  cent,  29  x  5.6  (24-35  x  4.8-5.9) m 

On  corn  agar,  culture  one  hundred  and  seventy-five  days  old;  conidia 
only  few,  chlamydospores  numerous,  terminal  and  intercalary: 
Chlamydospores:     0-septate,  in  mycelium,  11.3  x  9.3  (8.5-16  x  7.5-11)m 
1-septate,  in  mycelium,  16.3  x  9.9  (14-20  x  8-14) ^ 

On  hard  lima-bean  agar,  culture  twelve  days  old;  conidia  from  pseudo- 
pionnotes: 

Conidia:     0-septate,  4  per  cent  1  (percentage    may    vary     considerably 
1-septate,  15  per  cent  >    from  somewhat  greater  than   figures 
2-septate,  16  per  cent  J     given  here  to  nearly  zero) 
3-septate,  65  per  cent,  33  x  5.2  (27-37  x  4.7-5.6)m 

Average  of  the  above  measurements: 
Conidia:     0-septate,  9  per  cent,  12  x  3.7/u 

1-septate,  15  per  cent,  23  x  4.75iu 
2-septate,  18  per  cent,  27  x  5.3ju 
3-septate,  57.5  per  cent,  30.5  x  5.5jli 
4-septate,  0.5  per  cent,  35  x  5.5^1 

58.  Fusarium  Solani  (Mart.  p.  par.)  Ap.  et  Wr.  var.  suffuscum  n. 
var.  (Fig.  45,  k  to  t) 

Differs  from  F.  Solani  and  F.  Solani  var.  cyanum  mainly  by  typically 
well-developed,  uniform,  fine,  aerial  mycehum,  with  mass  of  chlamydo- 
spores at  maturity  which  gives  it  a  pale  brownish  tint;  by  sparse  conidial 
production  on  aerial  mycelium;  and  by  the  fact  that  sporodochia  are  usually 
few  and  distant  from  one  another. 

Hab.     On  rotted  tubers  of  Solanum  tuberosum,  Wisconsin. 


FusARiA  OF  Potatoes 


255 


The  average  size  and  occurrence  of  septation  type  of  conidJa  on  various 
media  are  as  follows: 
Conidia:     0-septate,  5.5  per  cent,  10.7  x  3.15At 

1-septate,  13.5  per  cent,  20  x  4.5^ 

2-septate,  17  per  cent,  25  x  4.5// 

3-septate,  60.5  per  cent,  30  x  5.41 /t 

4-septate,  3.5  per  cent,  34.5  x  5.5/: 

5-septate,  rare,  42.25  x  5.85^t 


59.  Fusarium  striatum  n.  sp.  (Figs.  Ic2  and  46;  PL  i,  fig.  2) 
Microconidia,  at  least  on  aerial  mycelium,  always  present.     Macro- 

conidia  of  shape  and  septation  intermediate  between  F.  Martii  and  F. 

Solani,   mostly  3-septate,   3,4.7x4.6   (31-36  x  4.4-5)  m,   from  colorless  to 


Fig.  46. —  Fusarium  striatum,  a,  Pseudopionnotal  conidia  from,  17 -days-old  culture  on 
slightly  acidified  hard  potato  agar;  b,  pseudopionnotal  conidia  from  58-days-old  culture  on  oats; 
c,  conidia  from  small  sporodochiimi  from  32-days-old  culture  on  hard  lima-bean  agar;  d,  sporo- 
dochial  conidia  from  86-days-old  culture  on  red  raspberry  cane  plug;  e,  pseudopionnotal  conidia 
from  13-days-old  potato  tuber  plug  {some  of  them  anastomosing);  f,  pseudopionnotal  conidia 
from  1 2-day s-old  culture  on  hard  lima-bean  agar;  g,  terminal  chlamydospores  produced  by  conidia 
from  64-days-old  culture  on  hard  lima-bean  agar  with  2  per  cent  glucose;  H,  chlamydospores 
from  32-days-old  culture  on  hard  lima-bean  agar;  i,  compound  conidiophore  from  34-days-old 
culture  on  hard  liiyia-bean  agar 


yellowish  glaucous  and  pale  turquoise  green,  in  numerous  minute  sporo- 
dochia;  sporodochia  often  converging  into  a  pseudopionnotes;  aerial 
mycelium  short  (rarely  up  to  3  millimeters  high),  "typically  (on  various 
agars)  fine,  uniformly  from  loose  to  very  loose,  downy  in  appearance, 
from  white  to  grayish  white;  substratum,  on  agars  rich  in  glucose,  from 
pale  glaucous  green  to  tawny  olive  and  sepia. 

Hab.     On  tubers  of  Solanum  tuberosum,  Colorado. 

Latin  description. — Microconidiis  —  saltem  in  aerio  mycelio  —  semper 
praesentibus;  macroconidiis  forma  et  septatione  inter  F.   Martii  et   F. 


256  C.  D.  Sherbakoff 

Solani  mediis,  plerumque  3-septatis,  34.7x4.6  (31-36  x  4.4-5) m,  ex 
hyalino  luteolo-glaucis  vel  pallide  "turquoise  green"  (R),  multis  minutis 
sporodochiis;  sporodochiis  saepe  in  pseudopionnotem  vergentibus;  aerio 
mycelio  brevi  (usque  ad  3  mm.  alt.)  typice  (in  agaribus  variis)  subtili, 
aequabiliter  laxo  vel  laxissimo,  pubescenti  viso,  ex  albo  caesio-albo;  sub- 
strate—  in  agaribus  perglucosis  —  ex  pallide  glauco-viridi  "tawny-olive" 
(R)  et  "sepia"  (R). 
Hab.  In  tuberibus  Solani  tuberosi,  Colorado,  Amer.  bor. 

Measurements  of  conidia  on  different  media  are  as  follows: 

On    slightly   acidified   hard    potato  agar,  culture  seventeen  days  old; 

conidia  from  pseudopionnotes: 

Conidia:     0-septate,  6  per  cent,  10.6  x  3.15  (8.5-12.5  x  2.5-3.5)ai 
1-septate,  10  per  cent,  19.5  x  3.9  (14-21  x  3-4.4)^ 
2-septate,  4  per  cent,  24.15  x  4.2  (21-27  x  3.5-4.7)m 
3-septate,  64  per  cent,  36.4  x  4.4  (26-50  x  4-5) /x 
4-septate,  16  per  cent,  47  x  4.5  (40-56  x  4.3-5.3)  m 
5-septate,  rare,  50  x  4.8  (47-56  x  4.3-5.3) m 

On  red  raspberry  cane  plug,  culture  eighty-six  days  old;  conidia  from 
a  sporodochium: 
Conidia:     0-septate,  3  per  cent 

1-septate,  7  per  cent,  19  x  3.5  (12-23  x  3-4.1))u 

2-septate,  2  per  cent 

3-septate,  88  per  cent,  41.6  x  5  (24-44  x  4-5.7) m 

4-septate,  very  rare,  43  x  5  (only  one  measured) 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  sixty-four  days 
old;  conidia  from  pseudopionnotes: 
Conidia:     0-septate,  10  per  cent 

1-septate,  22  per  cent,  22  x  4.1  (16-30  x  3.5-4.7)At 

2-septate,  10  per  cent 

3-septate,  58  per  cent,  31  x  4.6  (22-37  x  4.2-5) /x 

On  rye  grain,  culture  sixty-four  days  old;  conidia  from  a  sporodochium: 
Conidia:     0-septate,  39  per  cent 

1-septate,  28  per  cent,  20  x  3.9  (14-23  x  3.5-4.4) /x 

2-septate,  5  per  cent 

3-septate,  28  per  cent,  31  x  4.6  (24-36  x  4.3-5)m 


FusARiA  OF  Potatoes  257 

On  hard  lima-beau  agar,  culture  twelve  days  old: 

(1)  Conidia  from  a  sporodochium 

0-septate,  13  per  cent 

1-septate,  30  per  cent 

2-septate,  7  per  cent 

3-septate,  50  per  cent,  33  x  4.4  (24-44  x  3.6-4.7) m 

4-septate,  very  few 

(2)  Chlamydospores,  terminal  and  intercalary,  mostly  0-septate,  9  x  7.5 

(7-11 X 6-9) M 
On  same  medium  as  above,  culture  thirty-two  days  old;  conidia  from 

a  sporodochium: 

Conidia:     0-septate,  1  per  cent,  9  x  3.6m  (only  a  few  measured) 
1-septate,  20  per  cent,  20  x  3.9  (14-25  x  3.5-4.1)/x 
2-septate,  5  per  cent,  25  x  4.2  (23-30  x  4-4.4)  m 
3-septate,  73  per  cent,  35  x  4.6  (28-37  x  4-4.7) m 
4-septate,  1  per  cent,  41  x  4.7m  (only  a  few  measured) 

Average  of  the  above  measurements: 
Conidia:     0-septate,  12  per  cent,  10  x  3.4m 
1-septate,  19.5  per  cent,  20  x  3.9m 
2-septate,  5.5  per  cent,  24.5  x  4.2m 
3-septate,  60  per  cent,  34.7  x  4.6m 
4-septate,  3  per  cent,  43.7  x  4.7m 
5-septate,  very  rare,  50  x  4.8m 

60.  Fusarium  radicicola^''  Wr.  (Fig.  47;  PI.  vi,  fig.  8) 

Wollenweber,  H.  W.,  Journ.  Agr.  Research  2:257-258,  PI.  xvi,  fig.  k, 
1914. 

Microconidia  nearly  straight  near  base,  slightly  curved  in  upper  third 
of  their  length,  with  from  somewhat  rounded  to  distinctly  constricted 
apex,  slightly  pedicellate,  mostly  3-septate,  35.2x4.7  (31-40  x  4.6-5) m; 
0-  and  1-septate,  microconidia  very  common,  0-septate  measuring  8  x  3m; 
chlamydospores  common,  terminal  and  intercalary,  mostly  0-  and  1-sep- 
tate,   0-septate    averaging    9-10  x  8. 7-8. 8m;     pseudopionnotes    typically 

"  In  an  article  which  appeared  after  this  work  was  ready  for  press,  Dr.  Wollenweber  (1914)  describes  a 
new  species  of  Fusarium  (F.  radicicola)  with  which  this  organism  appears  identical.  No  cultural  com- 
parisons have  been  possible,  but  the  type  of  tuber  rot  and  type  of  conidia  are  alike,  and  in  certain  instances 
material  for  study  has  come  from  the  same  region.  Possibly  any  differences  may  be  accounted  for  in  the 
difference  in  strains  studied. 


258 


C.  D.  Sherbakoff 


absent;  plectenchymic  sporodochia  often  present;  aerial  mycelium  well 
developed;  color  of  conidia  from  white  to  olive,  of  substratum  from  pale 
yellowish  to  olive  (on  agar  rich  in  glucose  and  on  potato  tuber  plug). 

Hab.  On  rotted  tubers  of  Solanum  tuberosum,  in  Oregon,  Idaho,  and 
California. 

F.  radicicola  differs  from  F.  Martii  and  F.  Martii  var.  viride  by  shorter 
macroconidia;  from  F.  Martii  var.  minus  by  absence  of  prominent  plecten- 
chymic sporodochia;  and  from  F.  striatum  by  well-developed  aerial  my- 
celium and  by  typical  absence  of  pseudopionnotes. 


Fig.  47. —  Fusarium  radicicola.  a,  Conidiophore,  b,  sporodochial  conidia,  from  67-days-old 
culture  on  potato  stem  plug;  c,  aerial  and  pseudopionnotal  conidia  from  12-days-old  culture 
on  hard  lima-bean  agar;  d,  conidiophore  {magnification  250  times)  from  ^8-days-old  culture 
on  rye  straxo;  e,  chlamydospores,  f,  aerial  conidia,  g,  conidiophore  (magnified  250  times),  from 
73-days-old  culture  on  red  raspberry  cane  plug;  H,  conidia  from  the  surface  of  original  stem- 
end  rotted  potato  tuber;  \,  conidia  from  48-days-old  culture  on  rye  straw;  3,  conidia  from  pseudo- 
pionnotes in  7-days-old  colony  in  petri  dish  on  hard  potato  agar;  k,  conidiophore  from  the  sur- 
face of  original  stem-end  rotted  potato  tuber;  l,  aerial  conidia  close  to  substratum  from  64-days-old 
culture  on  hard  lima-bean  agar;  u,  chlamydospores  produced  in  mycelium  and  conidia  from 
1 73-days-old  culture  on  corn  agar;  n,  conidia,  o,  spore  ball,  both  magnified  250  times,  from 
3-days-old  hanging  drop  culture  in  potato  decoction  in  van  Tieghem.  cell;  p,  chlamydospores 
from  82-days-old  culture  on  potato  tuber  plug;  q,  conidia  and  conidiophores  from  26-days-old 
culture  on  oats 


Production  of  macroconidia  in  sporodochia  was  observed  to  be  abun- 
dant only  under  certain  conditions  (not  well  determined  as  yet),  but 
usually  micro  conidia  alone  are  the  dominant  type.  The  Oregon  speci- 
mens, from  which  cultures  of  the  fungus  were  first  obtained,  showed  a 


FusARiA  OF  Potatoes  259 

dark,  depressed  area  of  dry  rot  at  the  stem  end  of  the  tubers,  with  cream- 
white^  dense  tufts  of  conidiophores,  up  to  1  centimeter  high  and  powdered 
with  conidia.  (For  microscopic  characters  see  figure  47.)  Pure  cultures 
of  this  organism  were  obtained  both  from  the  aerial  conidia  and  from 
plantings  of  the  rotted  tissues  of  the  tubers. 

The  organisms  in  general  differ  much  from  F.  striatwn,  but  in  certain 
cultures  (in  sporodochia-producing  stage  on  whole  steamed  potato  tubers) 
resemble  it  very  closely. 

Measurements  of  conidia  on  different  media  are  as  follows: 

On  potato  tuber  plug,  culture  eighty-two  days  old: 

(1)  Conidia  from  aerial  mycelium 

Conidia:     0-septate,  95  per  cent,  8x3  (6-15  x  2.1-4)/^ 

1-septate,  5  per  cent,  15  x  4  (13-21  x  3.4-4.4) /i 
3-septate,  rare 

(2)  Chlamydospores,  intercalary  and  terminal,  unicellular  aiid  in  chains 

0-septate,  9.8  x  8.7  (5.2-16  x  5.2-12) m 

On  hard  lima-bean  agar  with  2  per  cent  glucose,  culture  sixty-four 
days  old: 

(1)  Conidia  from  aerial  mycelium  close  to  substratum 
Conidia:     0-septate,  80  per  centl 

1-septate,  17  per  cent  \  (size  same  as  above) 
2-septate,  2  per  cent  j 

3-septate,  1  per  cent,  33  x  4.8  (22-41  x  4.3-5.2)/* 
4-septate,  rare,  45  x  4.8  (only  a  few  measured) 

(2)  Chlamydospores 

0-septate,  9.5  x  8.8  (6.1-12  x  5.2-11)^ 
1-septate,  18  x  10  (16-22  x  5-12)^ 

On  hard  lima-bean  agar,  culture  twelve  days  old: 

(1)  Conidia  from  aerial  mycelium 
Conidia:     0-septate,  60  per  cent 

1-septate,  30  per  cent 

2-septate,  1  per  cent 

3-septate,  6  per  cent,  37  x  4.5  (28-48  x  4-5.3) /x 

4-septate,  3  per  cent,  43.6  x  5  (40-49  x  4.3-5.2)^ 

5-septate,  rare,  size  about  that  of  4-septate 

(2)  Chlamydospores,  mostly  0-septate,  9  x  8.7/* 


260  C.  D.  Sherbakoff 

On  whole  steamed  potato  tuber,  culture  sixty  days  old;  conidia  from  a 
sporodochium : 
Conidia:     0-septate,  11  per  cent 

1-septate,  21  per  cent 

2-septate,  8  per  cent 

3-septate,  60  per  cent,  31  x  4.8  (29-38  x  4.2-5.5)^ 

4-septate,  very  rare 

On  oat  grain,  culture  fifty-seven  days  old ;  conidia  from  a  sporodochium, 
septation  as  above: 

Conidia:     3-septate,  35.2  x  4.7  (25-42.5  x  4.2-5)/x 
4-septate,  43  x  5n  (only  one  measured) 

On  potato  stem  plug,  culture  seventy  days  old;  conidia  from  a  sporo- 
dochium, septation  approximately  that  given  above: 
Conidia:     3-septate,  35.2  x  5  (24.5-38  x  3.7-5.5) ju 

4-septate,  41.6  x  5.8/i  (only  one  measured) 

On  hard  potato  agar,  culture  ten  days  old;   conidia  from  aerial  myce- 
lium close  to  substratum: 
Conidia:     0-septate,  30  per  cent 

1-septate,  10  per  cent 

2-septate,  5  per  cent 

3-septate,  50  per  cent,  40  x  4.6  (32-46  x  4.3-4.9) m 

4-septate,  5  per  cent,  47  x  4.8  (45-49  x  4.5-5) /x 

Average  of  the  above  measurements: 
Conidia:     0-septate,  56  per  cent  (from  11  to  95  per  cent),  8  x  3;t 
1-septate,  16  per  cent  (from  5  to  30  per  cent),  15  x  4)li 
2-septate,  3  per  cent  (from  0  to  8  per  cent) 
3-septate,  23  per  cent  (from  0  to  60  per  cent),  35.2  x  4.73m 
4-septate,  2  per  cent  (from  0  to  5  per  cent),  43.9  x  5.1)u 
5-septate,  very  rare,  size  about  that  of  4-septate 

61.  Fusarium  coeruleum  (Lib.)  Sacc.  (Figs.  IB2  and  48;   PI.  i,   figs.  5 
and  6;  PL  vi,  fig.  4) 

Syn.  Fusarium  violaceum  Fuckel.     1869. 

Selenosporium  coeruleum  Libert,  in  herbarium. 

Cf.  Saccardo,  Syll.  Fung.  4:705.     1886.     Appel,  O.,  and  Wollenweber, 
H.  W.,  Arb.  K.  biol.    Anst.    Land-  u.    Forstw.  8:84-91,   PI.  m   fig.   6, 


FusARiA  OF  Potatoes 


261 


text  fig.  6.     1910.     WoUenweber,  H.  W.,  Phytopath.  3:31,  44,  45,  Fig.  Ic. 
1913. 

Microconidia  of  larger  size  than  those  of  other  species  of  section  Mar- 
tiella,  0-septate,  about  16  x  4.7At.  Macroconidia,  for  the  largest  part,  of 
an  even  diameter  or  somewhat  broader  toward  the  base,  only  slightly 
curved  near,  and  more  or  less  rounded  at,  the  apex,  never  apically  con- 
stricted, mostly  apedicellate  or  with  ventrally  depressed  basal  cell,  mostly 
3-septate,  33.3x5  (30-36  x  4.5-5.4) /x;  aerial  mycelium  usually  medium 


Fig.  48. —  Fusarium  coeruleum.  A,  Pseudopionnotal  conidia,  B,  conidiophore,  from  8-days- 
old  colony  in  petri  dish  on  hard  potato  agar;  c,  chlamydospores,  d,  coremium-like  form  of  mycelial 
growth  with  conidiophores,  e,  pseudopionnotal  conidia,  from  35-days-old  culture  on  potato  tuber 
plug;  F,  conidiophore  from  62-days-old  culture  on  rye  straw;  g,  conidia  {some  with  chlamydo- 
spores), n,conidiophore  {magnified  250  times) ,  from  54-days-old  culture  on  rye  straw;  i,  conidia 
from  small  sporodochium,  j,  conidiophore,  from  79-days-old  culture  on  red  raspberry  cane  plug;  K, 
chlamydospores,  l,  pseudopionnotal  conidia,  from  22-days-old  culture  on  hard  potato  agar.  A, 
B,  F,  G,  and  H  are  from  strains  isolated  from  rotted  potato  tubers  received  from  American  sources, 
the  remainder  are  from  the  culture  received  from  Dr.  WoUenweber 


well  developed,  feltlike  in  age,  of  from  white,  bluish  white,  and  olive-buff 
to  dusky  slate  violet,  on  potato  agar  rich  in  glucose,  and  to  slate  purple 
on  corn  meal  agar;  substratum,  on  potato  agar  rich  in  glucose,  from  deep 
hyssop  violet  to  indian  lake,  ocher-red,  and,  in  older  cultures,  violet- 
carmine;  color  of  conidia  from  orchraceous  orange,  on  strong  acid  agars, 
to  pale  buff  and  mouse  gray,  or  often  blue,  on  neutral  media. 
Hab.     On  rotted  tubers  of  Solanum  tuberosum,  common  in  Europe  and 


262  C.  D.  Sherbakoff 

America.  Cause  of  most  of  Fusarial  rot  on  potatoes  in  storage,  often 
occurring  in  association  with  other  Fusaria. 

The  organism  was  repeatedly  isolated  by  the  writer  from  diseased 
tubers,  and  every  strain  isolated  proved  capable  of  producing  more  or 
less  dark-colored  dry  rot  on  tubers.  It  may  be  mentioned  here  that  a 
white  rot  of  tubers  can  be  produced  by  certain  species  of  Fusarium  of  the 
Elegans  section,  such  as  F.  lutulatum.  A  rot  distinctly  striate  in  ap- 
pearance was  often  produced  by  inoculation  with  F.  striatum;  a  brownish 
rot  of  tubers  is  caused  by  F.  trichothecioides;  and  a  more  or  less  pinkish 
rot  with  large  cavities,  more  or  less  covered  with  red  masses  of  macro- 
conidia,  is  produced  by  F.  subulatum  and  F.  subulatum  var.  hrevius. 

Of  all  these,  F.  coeruleum  is  the  commonest  and  most  vigorous  wound 
parasite  of  potato  tubers;  the  next,  perhaps,  is  F.  subulatum  and  its 
variety. 

Measurements  of  conidia  of  a  few  strains  of  the  species  on  different 
media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,   culture  twenty-two  days  old; 
conidia  from  pseudopionnotes,  strain  66: 
Conidia:     0-septate,  5  per  cent,  16  x  4.7  (6-28  x  4.3-5.5) ^ 
1-septate,  9  per  cent,  21  x  4.7  (17-27  x  4.4-5.3) /i 
2-septate,  10  per  cent,  25  x  5.3  (18-32  x  4.6-5.9) m 
3-septate,  75  per  cent,  30  x  5.4  (20-40  x  4.7-6. 1)m 
4-septate,  1  per  cent,  36  x  5.5  (33-40  x  5.2-6.1)m 

On  red  raspberry  cane  plug,  culture  seventy-nine  days  old ;  conidia  from 
a  sporodochium,  strain  66;  3-septate,  up  to  100  per  cent,  33x5.4  (22- 
40  X  4.8-6)ai;  average  septation  being 
Conidia:     0-septate,  3  per  cent 

1-septate,  11  per  cent 

2-septate,  8  per  cent 

3-septate,  78  per  cent 

4-septate,  rare 

On  corn  meal  agar,  culture  one  hundred  and  seventy-five  days  old; 
strain  53;  very  few  conidia  observed;  chlamydospores  numerous: 
Chlamydospores:     0-septate,  8  x  7.5  (5.2-10.5  x  5.2-9)^ 
1-septate,  11.7  x  7.7  (9.2-14  x  7-8.5) m 
Also  in  chains  in  mycelium,  9  (7.8-ll)/x  in  diameter 


FusARiA  OF  Potatoes  263 

On  hard  potato  agar,  culture  one  hundred  and  fifty  days  old;  conidia 
from  a  sporodochium,  strain  96: 
Conidia:     0-septate,  10  per  cent 

1-septate,  12  per  cent 

2-septate,  7  per  cent 

3-septate,  71  per  cent,  36  x  5.1  (33-40  x  4.4-5.5) m 
Chlamydospores :  0-septate,  in  conidia,  average  size  8.8  x  8^ 

On  potato  tuber  plug,  culture  eighty-five  days  old;  conidia  from  a  pseu- 

dopionnotes,  strain  66: 

Conidia:     0-septate,  5  per  cent 
1-septate,  8  per  cent 
2-septate,  4  per  cent 
3-septate,  68  per  cent,  34.2  x  4.5m 
4-septate,  9  per  cent,  42  x  4.6m  (only  one  measured) 
5-septate,  6  per  cent,  55  x  5.5m  (only  two  measured) 

On  rye  straw,  culture  fifty-four  days  old;  conidia  from  a  sporodochium, 

strain  96: 

Conidia:     0-septate,  2  per  cent 

1-  to  2-septate,  5  per  cent 

3-septate,  89  per  cent,  33.5  x  5.1  (30-37  x  4-6) m 

4-septate,  4  per  cent,  33  x  6.1m  (only  one  measured) 

On  rye  straw,  culture   fifty  days  old;    conidia   from  a  sporodochium, 
strain  66: 
Conidia:     0-  to  2-septate,  5  per  cent 

3-septate,  88  per  cent,  30.5  x  4.9  (28-33  x  4.5-5.3)  m  (only  three 

measured) 
4-septate,  7  per  cent,  33.2  x  5.1m  (only  one  measured) 

On   rye    straw,    culture    forty-three    days    old;    conidia  from  a  sporo- 
dochium, strain  53: 
Conidia:     0-  to  2-septate,  23  per  cent 

3-septate,  73  per  cent,  35  x  5  (25-46.2  x  4.7-5.3)m 
4-septate,  4  per  cent,  50  x  5m  (only  one  measured) 

On  potato  hard  agar,  culture  eight  days  old;  strain   190: 
Conidia:     0-  to  2-septate,  2  per  cent 
3-septate,  80  per  cent 
4-  and  5-septate,  10  per  cent 
6-  and  7-septate,  8  per  cent,  58  x  5.6  (57-60  x  5.2-6) m 


264 


C.  D.  Sherbakoff 


The  greatest  septation  observed  was  in  a  culture  fifteen  days  old  on  oat 
grains.     This  was  a  9-septate  conidium  measuring  39  x  5.2/i. 

Average  of  the  above  measurements: 
Conidia:     0-septate,  about  4  per  cent,  16  x  4.7ai 

1-septate,  about  6  per  cent,  21  x  4.7/z 

2-septate,  about  5  per  cent,  25  x  5.3/i 

3-septate,  about  78  per  cent,  33.3  x  5n 

4-septate,  about  4.5  per  cent,  39  x  5.26/* 

5-septate,  about  2  per  cent,  55  x  5.5/i 

6-  and  7-septate,  about  0.5  per  cent,  58  x  5.6/1 
Appel  and  Wollenweber's  measurements  for  3-septate  conidia  average 
36x5.25  (31-40  X  4.5-5.5)/i 


RAMULARIA  (Unger)  Fries  (Fig.  1,  a  to  c) 
Unger,  F.,   Exantheme  der  Pflanzen,  page  169.     1833.     Fries,   E.  M., 
Summa    vegetabilium    Scandinaviae,   page  493.     1849. 
Cf .  Wollenweber,  H.  W.,  Phytopath.  3 :  33.     1913.    Wol- 
lenweber,  H.  W.,  Phytopath.  3:207-211.     1913. 

Differs  from  Fusarium  mainly  by  nearly  cylindrical, 
apedicellate  conidia,  with  rounded  apex;  plectenchymic 
stromata  flat  to  well-developed,  wartlike,  short 
column-like  structures  typically  present;  conidia  borne 
on  conidiophores  on  aerial  mycelium,  or  on  plecten- 
chymic substratum;  microconidia  (that  is,  a  distinct, 
Fig.  49. — Ramularia  abbreviated  type  of  conidia)  absent. 
eudidyma.     a,  Co- 

1.  Ramularia  eudidy Via  y^v.     (Figs.  1b  and  49) 

Wollenweber,  H.  W.,  Phytopath.  3:221-222,  PI.  xxi, 

fig.  c.     1913. 

Syn.  Fusisporium  didymum  Hartig.     1846. 

Fusarium  didymum  (Hart.)  Lindau.     1909. 
Fv^arium  didymum  (Hart.)  Ap.  et  Wr.     1910. 
Ramularia  didyma  (Hart.)  Wr.     1913. 

Conidia  nearly  cylindrical,  with  both  ends  rounded 
or  basal  ends  sometimes  papillate,  mostly  1-septate, 
23x4.87    (21-26  x4.7-5)/i;^«    0-  to    2-septate    conidia 

data  (1913  c  :  234)  the  average  size  of  l-septate  conidia  is  26.4  x  5  (21- 


nidia  from  aerial 
mycelium  from  55- 
days-old  culture  on 
red  raspberry  cane 
plug;  B,  sporodo- 
chial  conidia  from 
1 53-day  s-old  cul- 
ture on  hard  lima- 
bean  agar;  c,  co- 
nidia from  aerial 
mycelium  from  25- 
days-old  culture  on 
slightly  acidified 
hard  potato  agar 


s8  According  to  Wollenweber' 
29  X  4. 25-5.5) M. 


FusARiA  OF  Potatoes 


265 


also  found,  3-septate  very  rare;  chlamydospores  mostly  intercalary, 
8-11 M  in  diameter;  color  of  spore  mass,  from  white  to  yellowish;  color  of 
plectenchyma,  dense  brown. 

Hab.  On  decaying  tubers  of  Solanum  tuberosum  and  on  roots  of  Ruhus 
idceus,  also  in  soil,  Europe. 

The  organism  was  not  isolated  by  the  writer,  but  was  briefly  studied 
from  a  culture  received  through  the  courtesy  of  Dr.  Wollenweber. 

2.  Ramularia  Magnusiana  (Sacc.)  Lindau  (Figs.  Ic  and  50) 
Cf.  Wollenweber,  H.  W.,  Phytopath.  3:221,  234;  Pis.  xx,  figs,  f  to  h, 
and  XXI,  fig.  a.     1913. 

Conidia  of  the  same  type  as  those  of  R.  eudidijma,  also  mostly  1-septate, 


Fig.  50. —  Ramularia  Magnusiana.  a,  Conidia  from  aerial  mycelium,  b,  conidiophores , 
from  ll-days-old  culture  in  a  petri  dish  on  neutral  hard  potato  agar;  c,  chlamydospores,  d,  sporo- 
dochial  conidia,  from  51 -days-old  culture  on  red  raspbery  cane  plug;  e,  chlamydospores  from 
ll-days-old  culture  in  a  petri  dish  on  neutral  hard  potato  agar;  f,  conidia  from  aerial  mycelium 
from  22-days-old  culture  on  slightly  acidified  hard  potato  agar;  g,  sporodochial  conidia  from 
153-days-old  culture  on  hard  lima-bean  agar  with  2  per  cent  glucose 


23.6x4.3  (18-27x3.5-5)^1;^^  0- to  3-septate  conidia  also  occurring,  not 
numerous,  sometimes  catenulate ;  plectenchyma  from  olive  to  coffee  brown. 
Much  like  R.  Candida  (Ehr.)  Wr.,  differing  from  it  by  old  rose  color  on 
rice  and  by  thinner  conidia  sometimes  borne  in  chains.  0-septate  chlamy- 
dospores 10  X  11  (7-11  X  9-16)  m;  1-,  2-,  and  pluri-septate  chlamydospores 
also  occurring. 

Hab.  Common  on  tubers  of  Solanum  tuberosum,  also  found  on  the 
leaves  of  Trientalis  and  on  the  roots  of  Acer,  in  Europe  and  America. 

The  fungus  was  isolated  several  times  from  rotted  potato  tubers.  New 
York,  the  tubers  being  covered  with  from  a  few  to  many,  from  dark  brown 

"  The  size  is  after  Wollenweber  (1913  c :  234). 


266  C.  D.  Sherbakoff 

to  brick  red,  plectenchymic  bodies,  from  2  to  3  millimeters  in  diameter  and 
from  1  to  4  millimeters  high,  often  bearing  characteristic,  almost  cylin- 
drical, usually  1-septate,  conidia. 

The  strains  isolated  by  the  writer  differ  from  those  described  by  Wol- 
lenweber,  by  more  reddish  color  of  plectenchyma,  by  somewhat  narrower 
conidia  and  larger  (?)^*'  chlamydospores,  and  by  the  absence  of  persistent 
conidial  chains. 

Measurements  of  conidia  of  strain  63  on  a  few  different  media  are  as 
follows : 

On  slightly  acidified  hard  potato  agar,  culture  twenty-two  days  old; 

conidia  from  aerial  myceUum: 

Conidia:     0-septate,  rare 

1-septate,  95  per  cent,  26.5x4.1  (18-30  x  3.5^4.7)m 
2-septate,  5  per  cent,  about  the  same  size  as  1-septate 

On  red  raspberry  cane  plug,  culture  fifty-one  days  old;  conidia  from 
a  sporodochium: 
Conidia:     0-septate,  50  per  cent,   13x3   (8-28  x  2.6-4) /x 

1-septate,  50  per  cent,  27  x  3.9  (24-31  x  3-4.3)^ 

On  hard  lima-bean  agar,  culture  one  hundred  and  fifty-three  days  old; 
conidia  from  a  sporodochium: 

Conidia:     0-septate,  1  per  cent,  10  x  3.4  (7.9-12.3  x  3-3.5)^ 
1-septate,  99  per  cent,  26  x  3.8  (20-32  x  3.5-4V 

Average  of  the  above  measurements: 
Conidia:     0-septate,  17  per  cent,  11.5x3.9/x 
1-septate,  81  per  cent,  26.5  x  3.9m 
2-septate,  0  to  5  per  cent,  same  as  1-septate 

The  average  size  of  conidia  according  to  Wollenweber's  measurements  is: 
Conidia:     0-septate,  rare,  14  x  3.8^ 

1-septate,  100  per  cent,  23.6  x  4.3ai 
3-septate,  rare,  30  x  5^ 

It  is  possible  that  strain  63,  on  a  thorough  comparative  study  of  it 
with  R.  Magnusiana,  may  prove  to  be  a  distinct  variety;  but  it  is  evident 
that  the  resemblance  between  the  two  in  all  important  characters  is  close 
enough  to  warrant  its  being  placed  in  the  species  R.  Magnusiana. 

«»  Wollenweber  does  not  give  the  size  of  chlamydospores,  but  it  can  ba  interpreted  that  it  is  the  same 
as  for  R.  Candida  (Ehr.)  Wr.,  namely,  5-8/i  in  diameter.  Chlamydospores  of  the  strains  described  here  on 
corn  meal  agar  in  cultures  one  hundred  and  seventy-three  days  old  measured  10  x  11  (7-11  x  9-16)  m- 


FusARiA  OF  Potatoes 


267 


3,  Ramularia  Solani  n.  sp.  (Figs.  1a  and  51) 

Coiiidia  from  nearly  cylindrical  to  slightly  curved,  with  both  ends 
rounded  or  with  basal  cell  slightly  papillate,  mostly  1-  and  2-septate; 
1-septate  measuring  29.5x6.5  (28-30  x  6.2-6.7) m,  and  2-septate  meas- 
uring 32x6.4  (26-33.7  X  6.3-6.8))u;  plectenchyma  flat,  usually  chocolate 
brown;  aerial  mycelium  from  2  to  4  millimeters  high,  from  medium  dense 
to  medium  loose,  from  chamois  to  deep  ohve-buff,  on  potato  agar  rich  in 
glucose,  often  with  a  chocolate-drab  tinge;  substratum,  on  the  same 
medium,  in  zones  of  from  sepia  to  tawny  olive,  and  in  old  cultures  to 
Saccardo's  amber;  conidia  in  mass  from  nearly  white  to  deep  olive-buff; 
no  chlamydospores  observed. 

Hab.     On  rotted  tubers  of  Solarium  tuberosum,  New  York. 


Fig.  51. —  Ramularia  Solani.  a,  Sporodochial  conidia  from  12-days-old  culture  on  oats; 
B  and  c,  conidiophores  from  34-days-old  culture  on  hard  lima-bean  agar;  d,  conidia  from  aerial 
mycelium  from  25 -days-old  culture  on  slightly  acidified  hard  potato  agar;  e,  conidia  from  aerial 
mycelium  from  34-days-old  culture  on  hard  lima-bean  agar;  f,  sporodochial  conidia  from  8- 
days-old  culture  on  hard  lima-bean  agar;  g,  sporodochial  conidia  from  55-days-old  red  rasp- 
berry cane  plug;  h,  sporodochial  conidia  from  67 -days-old  flask  culture  on  hard  potato  agar 
with  2  per  cent  glucose 


Latin  descriptio7i. — Conidiis  ferme  cylindricis  vel  parum  curvatis, 
utrisque  finibus  rotundatis  vel  cella  infima  parum  papillata,  plerumque 
1-2-septatis;  conidiis  1-septatis,  29.5x6.5  (28-30  x  6.2-6.7) /x,  vel  2-sep- 
tatis,  32x6.4  (26-33.7  x  6.3-6. 8)/x;  plectenchymate  piano,  plerumque 
"chocolate  brown"  (R);  aerio  mycelio  2-4  mm.  alt.,  e  mediocriter  denso 
mediocriter  laxo,  e  "chamois"  (R)  "olive-buff"  (R),  saepe  in  agare  So- 
lani tuberosi  perglucoso  "chocolate-drab"  (R)  tincto;  substrato,  eodem  in 
agare,  e  "sepia"  (R)  "tawny  ohve "  (R)  in  zonis,  vel  in  culturis  maturis 


268  CD.  Sherbakoff 

"Saccardo's  amber"  (R);  conidiis  in  totum  e  ferme  albo  olivaceo-gilvis; 
nullis  chlamydosporis. 

Hab.  In  tuberibus  putridis  Solani  tuberosi,  New  York,  Amer.  bor. 

Measurements  of  conidia  on  different  media  are  as  follows: 

On  slightly  acidified  hard  potato  agar,  culture  twenty-five  days  old; 

conidia  from  a  sporodochium: 

Conidia :     0-septate,  rare 

1-septate,  25  per  cent,  28-35  x  5.5-6.3/1 
2-septate,  45  per  cent,  26  x  6.3  (29-39  x  6.7) /x 
3-septate,  30  per  cent,  37  x  6.5  (30-41  x  6.3-7)m 

On  red  raspberry  cane  plug,  culture  fifty-five  days  old ;  conidia  from  a 
sporodochium : 

Conidia:     1-septate,  63  per  cent,  30  x  6.7  (20-34  x  5.5-7.4)^ 
2-septate,  37  per  cent,  33  x  6.8  (25-37  x  6.5-7.4)^ 

On  the  same  medium  as  above,  culture  one  hundred  and  thirty-six 

days  old;  conidia  from  a  sporodochium: 

Conidia:     0-septate,  few,  19  x  5.4ju  (only  a  few  measured) 
1-septate,  30  per  cent,  28  x  6.2  (20-32  x  5.2-6.8)At 
2-septate,  62  per  cent,  33  x  6..5  (28-40  x  6-7)  m 
3-septate,  8  per  cent,  35  x  6.5  (31-40  x  6-7)// 

On  hard  lima-bean  agar,  culture  eight  days  old;  conidia  from  a  sporo- 
dochium : 

Conidia:     1-septate,  44  per  cent,  30  x  6.3  (22-35  x  5.5-6.5) m 
2-septate,  49  per  cent,  33.7  x  6.4  (29-39  x  6-6.6)m 
3-septate,  7  per  cent,  36  x  6.5  (31-40  x  6-6.6))u 
On  same  medium  and  from  same  sporodochium  as  above,  culture  thirty- 
four  days  old: 
Conidia:     0-septate,  rare 

1-septate,  46  per  cent,    30  x  6.2  (23-37  x  5.4-6.5) m 
2-septate,  35  per  cent,  33.6  x  6.3  (24-39  x  5.8-6.5)^ 
3-septate,  19  per  cent,  36.9  x  6.5  (32-39  x  6.1-7)/x 
Average  of  the  above  measurements: 
Conidia:     0-septate,  rare,  19  x  5.4/x 

1-septate,  42  per  cent,  29.5  x  6.5/i 
2-septate,  45  per  cent,  32  x  6.4/i 
3-septate,  13  per  cent,  36  x  6.5/* 


FusARiA  OF  Potatoes  269 

This  organism,  together  with  Fusarium  udum  var.  Solani,  was  isolated 
by  the  writer  only  once,  from  a  planting  of  diseased  tissues  of  a  potato 
tuber  affected  with  a  superficial  dry  rot,  received  from  Long  Island, 
New  York. 

By  the  shape  and  size  of  its  conidia  it  very  closely  resembles  R.  macro- 
spora  Fres.  (see  Wollenweber  1913  c:  222-223,  235,  PI.  xx,  a  and  b,  and 
PL  XXI,  e),  but  differs  mainly  by  the  absence  of  oval,  continuous  conidia 
on  aerial  mycelium,  and  by  the  absence  of  chlamydospores.^^ 

LITERATURE  CITED 

Appel,  Otto,  and  Wollenweber,  H.  W. 

1910  Grundlagen  einer  monographic  der  gattung  Fusarium  (Link). 
K.  Biol.  anst.  Land- und  Forstw.  Arb.  8:1-207,  figs. 
1-  10,  Pis.  1-3. 

Jamieson,  C.  O.,  and  Wollenweber,  H.  W. 

1912  An  external  dry  rot  of  potato  tubers  caused  by  Fusarium 

trichothecioides  WoUenw.     Washington  Acad.  Sci.     Journ. 
2 : 146-152. 

Lewis,  Charles  E. 

1913  Comparative  studies  of  certain  disease-producing    species  of 

Fusarium.     Maine  Agr.  Exp.  Sta.     Bui.  219:203-258,  figs. 
86-118. 

Lindau,  G. 

1905     Die  Pilze.     Rabenhorst's  Kryptogamen  Flora  8:391-392. 
1908     Sorauer's  Handbuch  der  Pflanzenkrankheiten  2:468-469. 
1908-1909     Die  Pilze.     Rabenhorst's  Kryptogamen  Flora  9:336,  503, 
509,  517-588. 

Ridgway,  Robert. 

1912  Color  standards  and  color  nomenclature.     53  colored  plates, 

1115  named  colors. 

Shear,  C.  L.,  and  Wood,  Anna  K. 

19 1 3  Studies  of  fungous  parasites  belonging  to  the  genus  Glomerella. 

U.  S.  Plant  Indus.  Bur.     Bui.  252:5-110,  pis.  1-18. 

I  61  Chlamydospores  were  searched  for  very  carefully  in  cultures  on  different  media  and  of  different  ages, 
very  old  cultures  being  included,  but  were  never  observed.  According  to  Wollenweber  (1913  c :  208) 
such  organisms,  Ramularia-like  but  without  chlamydospores,  produce  perfect  forms  of  the  genus  Myco- 
sphaerella;  although  the  organism  described  here  under  tlie  name  oiR.  Solani,  when  grown  on  various  media, 
did  not  produce  chlamydospores,  nevertheless  it  has  been  retained  in  this  genua  because  of  its  otherwise 
perfect  resemblance  to  the  other  unquestionable  species  of  Ramularia. 


270  C.  D.  Sherbakoff 

Smith,  E.  F.,  and  Swingle,  D.  B. 

1904     The  dry  rot  of  potatoes  due  to  Fusarium  oxysporum.     U.  S. 
Plant  Indus.  Bur.     BuL  55:5-64,  figs.  1-2,  pis.  1-8. 

Thorn,  Charles. 

1910     Cultural    studies    of   species    of    Penicillium.     U.    S.    Animal 
Indus.  Bur.     Bui.  118:5-107,  figs.  1-36. 

Wilcox,  E.  Mead,  Link,  George  K.  K.,  and  Pool,  Venus  W. 

1913     A  dry  rot  of  the  Irish  potato  tuber.  Nebraska  Agr.  Exp.  Sta. 
Research  bul.  1:3-88,  figs.  1-15,  pis.  1-28. 

Wollenweber,  H.  W. 

1913  a     Studies    on    the    Fusarium    problem.     Phytopath.  3:24-50, 
fig.  1,  pi.  5. 

1913  b     Pilzparasitare  welkekrankheiten  der  kulturpflanzen.     Deut. 
Bot.  Gesell.     Ber.  31 :  17-34. 

1913  c     Ramularia,    Mycosphaerella,     Nectria,    Calonectria.       Eine 

morphologisch  pathologische  studie  zur  abgrenzung  von 
pilzgruppen  mit  cylindrischen  und  sichelformigen  konidien- 
formen.     Phytopath.  3 :  197-242,  pis.  20-22. 

1914  Identification  of  species  of  Fusarium  occurring  on  the  sweet 

potato,  Ipomoea  batatas.  Journ.  agr.  research  2:251-285, 
pis.  12-16. 

Submitted  for  publication  February  10,   1915. 


EXPLANATION  OF  PLATES 

All  the  plates  were  reproduced  by  three-color  process  from  living  cultures.  The  cultures 
were  in  all  cases,  unless  otherwise  specified,  fortj'  days  old  when  photographed,  and  were 
grown  at  laboratory  rooin  temperature  ranging  from  20°  to  25°  C. 

Cultures  of  Plates  I  to  IV  were,  with  a  few  specified  exceptions,  grown  on  hard  potato  agar 
with  10  per  cent  glucose,  and  were  kept  in  a  strong  diffuse  daylight  and  in  air  nearly  saturated 
with  moisture. 

All  cultures  of  Plates  V  to  VII  were  on  sterilized  potato  tuber  plugs  in  test  tubes  which 
were  kept  at  the  above  temperature  but  in  very  weak  diffuse  light. 

PLATE   I.     FUSARIA  OF  POTATOES 

Fig.  1.     Fusarium  Solani,   from  above 

Fig.  2.     F.  striatum,  from  above 

Figs.  3  and  4.     F.  Martii   var.  minus:     3,   on  acidified  medium  from  below;  4,    on  hard 

oat  agar  from  above 
Figs.  5  and  6.     F.  coeruleum,  from  above  and  below 
Figs.  7  and  8.     F.  o.xysporum  var.  resupinatum,  from  above  and  below 
Figs.  9  and  10.     F.  lutulatum  var.  zonatum,  from  above  and  below 
Figs.  11  and  12.     F.  selerotioides,  in  dark,  from  above  and  below 


PLATE  I-FUSARIA  OF  POTATOES 


PLATE  II.     FUSARIA  OF  POTATOES 

Figs.  1  and  2.     Fusarium   sclerotioides  var.   brevius,   from  above  and    below;    1,   culture 

fifteen  days  old 
Figs.  3  and  4.     F.  reddens  var.  Solani,  from  above  and  below 
Figs.  5  and  6.     F.  lutulatum,  from  above  and  below;  6,   culture  on  slightly  acidified  medium 

fifteen  days  old 
Figs.  7  and  8.     F.  arcuosporum,  from  above  and  below 

Figs.  9  and  10.    F.  lucidum,  from  above  and  below;    fig.  9,  culture  fifteen  daj's  old,  in  dark 
Fig.  11.    F.  subulatum,  from  above;  hard  oat  agar 
Fig.  12.    F.  subulatum  var.  brevius,  from  belo'w,  on  slightly  acidified  medium 


PLATE  II-FUSARIA  OF  POTATOES 


PLATE  III.     FUSARIA  OF  POTATOES 

Fig.  1.    Fusarium  sporotrichioides,  from  above;  in  dark 

Fig.  2.    F.  bullatum  var.  roseum,  from  above 

Figs.  3  and  4.  F.  arthrosporioides,  from  above  and  below;  in  dark 

Figs.  5  and  6.    F.  sanguineum  var.  pallidium,  from  above  and  below 

Figs.  7  and  8.    F.  sanguineum,  from  aVjove  and  Ijelow;  in  dark 

Figs.  9  and  10.    F.  ferruginosum,  from  above  and  below 

Figs.  11  and  12.    F.  clavatum,  from  above  and  below 


PLATE  III-FUSARIA  OF  POTATOES 


PLATE  IV.  FUSARIA  OF  POTATOES 

Figs.  1  and  2.    Fusarium  culmorum  var.  leteius,  from  above  and  below 

Fig.  3.    F.  subpallidum  var.  roseum,  from  above;  on  slightly  acidified  medium 

Fig.  4.    F.  discolor,  from  below 

Figs.  5  and  6.    F.  discolor  var.  triseptatum:  5,  from  above,  in  dark  on  neutral  medium; 

6,  from  above,  in  light  on  slightlj-  acidified  medium 
Fig.  7.    F.  caudatum  var.  Solani,  from  above,  neutral  medium 
Fig.  8.    F.  trichothecioides,  from  above 
Fig.  9.    F.  culmorum  from  above,  on  hard  oat  agar 
Fig.  10.    F.  culmorum  var.  leteius,  from  above,  on  hard  oat  agar 
Fig.  11.    F.  discolor  var.  sulphureum,  from  above 
Fig.  12.    F.  lucidum,  from  above,  slightly  acidified  medium,  fifteen  days  old 


PLATE  IV-FUSARIA  OF  POTATOES 


PLATE  V.  FUSARIA  OF  POTATOES 


Fig.  1. 

Fusarium  sclerotioides 

Fig.  2. 

F.  redolens  var.  Solani 

Fig.  3. 

F.  lutulatum 

Fig.  4. 

F.  lutulatum  var.  zonatum 

Fig.  5. 

F.  oxysporum  var.  resupinatum 

Fig.  6. 

F.  oxysporum 

Fig.  7. 

F,  oxysporum  var.  asclerotium 

Fig.  8. 

F.  cuimorum 

Fig.  9. 

F.  cuimorum  var.  leteius 

Fig.  10. 

F.  discolor  var.  triseptatum 

Fig.  11. 

F.  discolor 

Fig.  12, 

F.  subpallidura 

PLATE  V-FUSARIA  OF  POTATOES 


PLATE  VI.     FUSARIA  OF  POTATOES 


Fig.  1.    Fusarium  sanguineuin 

Fig.  2.    F.  ferrugiaosum 

Fig.  3:    F.  caudatum  var.  Solani 

Fig.  4.    F.  coeruleum 

Fig.  5.    F.  Martii  var.  viride 

Fig.  6.    F.  Martii  var.  minus 

Fig.  7.    F.  Solani 

Fig.  8.    F.  radicicola 

Fig.  9.    F.  anguioides  var.  caudatum 

Fig.  10.    F.  arcuosporum 

Fig.  11.    F.  anguioides 

Fig.  12.    F.  lucidum 


PLATE  VI-FUSARIA  OF  POTATOES 


PLATE  VII.     FUSARIA  OF  POTATOES 


Fig.  1.    Fusarium  truncaturn 

Pig.  2.    F.  clavatum 

Fig.  3.    F.  subulatum  var.  breviu.s 

Fig.  4.    F.  subulatum 

Fig.  5.    F.  metacroun 

Fig.  6.    F.  effusum 

Fig.  7.    F.  sanguineum  var.  paliidium 

Fig.  8.    F.  falcatum  var.  fuscum 

Fig.  9.    F.  arthrosporioides  var.  asporotrichius 

Fig.  10.    F.  biforme 

Fig.  11.    F.  arthrosporioide.s 

Fig.  12.    F.  diversisporum,  pseudopioiinotal  stage 


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PLATE  VII-FUSARIA  OF  POTATOES 


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